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Sample records for erisma uncinatum warm

  1. Structural and Biochemical Analysis of the Sheath of Phormidium uncinatum

    PubMed Central

    Hoiczyk, Egbert

    1998-01-01

    The sheath of the filamentous, gliding cyanobacterium Phormidium uncinatum was studied by using light and electron microscopy. In thin sections and freeze fractures the sheath was found to be composed of helically arranged carbohydrate fibrils, 4 to 7 nm in diameter, which showed a substantial degree of crystallinity. As in all other examined motile cyanobacteria, the arrangement of the sheath fibrils correlates with the motion of the filaments during gliding motility; i.e., the fibrils formed a right-handed helix in clockwise-rotating species and a left-handed helix in counterclockwise-rotating species and were radially arranged in nonrotating cyanobacteria. Since sheaths could only be found in old immotile cultures, the arrangement seems to depend on the process of formation and attachment of sheath fibrils to the cell surface rather than on shear forces created by the locomotion of the filaments. As the sheath in P. uncinatum directly contacts the cell surface via the previously identified surface fibril forming glycoprotein oscillin (E. Hoiczyk and W. Baumeister, Mol. Microbiol. 26:699–708, 1997), it seems reasonable that similar surface glycoproteins act as platforms for the assembly and attachment of the sheaths in cyanobacteria. In P. uncinatum the sheath makes up approximately 21% of the total dry weight of old cultures and consists only of neutral sugars. Staining reactions and X-ray diffraction analysis suggested that the fibrillar component is a homoglucan that is very similar but not identical to cellulose which is cross-linked by the other detected monosaccharides. Both the chemical composition and the rigid highly ordered structure clearly distinguish the sheaths from the slime secreted by the filaments during gliding motility. PMID:9683490

  2. Gene clusters for insecticidal loline alkaloids in the grass-endophytic fungus Neotyphodium uncinatum.

    PubMed

    Spiering, Martin J; Moon, Christina D; Wilkinson, Heather H; Schardl, Christopher L

    2005-03-01

    Loline alkaloids are produced by mutualistic fungi symbiotic with grasses, and they protect the host plants from insects. Here we identify in the fungal symbiont, Neotyphodium uncinatum, two homologous gene clusters (LOL-1 and LOL-2) associated with loline-alkaloid production. Nine genes were identified in a 25-kb region of LOL-1 and designated (in order) lolF-1, lolC-1, lolD-1, lolO-1, lolA-1, lolU-1, lolP-1, lolT-1, and lolE-1. LOL-2 contained the homologs lolC-2 through lolE-2 in the same order and orientation. Also identified was lolF-2, but its possible linkage with either cluster was undetermined. Most lol genes were regulated in N. uncinatum and N. coenophialum, and all were expressed concomitantly with loline-alkaloid biosynthesis. A lolC-2 RNA-interference (RNAi) construct was introduced into N. uncinatum, and in two independent transformants, RNAi significantly decreased lolC expression (P < 0.01) and loline-alkaloid accumulation in culture (P < 0.001) compared to vector-only controls, indicating involvement of lolC in biosynthesis of lolines. The predicted LolU protein has a DNA-binding site signature, and the relationships of other lol-gene products indicate that the pathway has evolved from various different primary and secondary biosynthesis pathways.

  3. Coregulated expression of loline alkaloid-biosynthesis genes in Neotyphodium uncinatum cultures.

    PubMed

    Zhang, Dong-Xiu; Stromberg, Arnold J; Spiering, Martin J; Schardl, Christopher L

    2009-08-01

    Epichloë endophytes (holomorphic Epichloë spp. and anamorphic Neotyphodium spp.) are systemic, often heritable symbionts of cool-season grasses (subfamily Pooideae). Many epichloae provide protection to their hosts by producing anti-insect compounds. Among these are the loline alkaloids (LA), which are toxic and deterrent to a broad range of herbivorous insects but not to mammalian herbivores. LOL, a gene cluster containing nine genes, is associated with LA biosynthesis. We investigated coordinate regulation between LOL-gene expression and LA production in minimal medium (MM) cultures of Neotyphodium uncinatum. Expression of all LOL genes significantly fit temporal quadratic patterns during LA production. LOL-gene expression started before LA were detectable, and increased while LA accumulated. The highest gene expression level was reached at close to the time of most rapid LA accumulation, and gene expression declined to a very low level as amounts of LA plateaued. Temporal expression profiles of the nine LOL genes were tightly correlated with each other, but not as tightly correlated with proC and metE (genes for biosynthesis of precursor amino acids). Furthermore, the start days and peak days of expression significantly correlated with the order of the LOL-cluster genes in the genome. Hierarchical cluster analysis indicated three pairs of genes-lolA and lolC, lolO and lolD, and lolT and lolE-expression of which was especially tightly correlated. Of these, lolA and lolC tended to be expressed early, and lolT and lolE tended to be expressed late, in keeping with the putative roles of the respective gene products in the LA-biosynthesis pathway. Several common transcriptional binding sites were discovered in the LOL upstream regions. However, low expression of P(lolC2)uidA and P(lolA2)uidA in N. uncinatum transformants suggested induced expression of LOL genes might be subject to position effect at the LOL locus. PMID:19366635

  4. Coregulated expression of loline alkaloid-biosynthesis genes in Neotyphodium uncinatum cultures.

    PubMed

    Zhang, Dong-Xiu; Stromberg, Arnold J; Spiering, Martin J; Schardl, Christopher L

    2009-08-01

    Epichloë endophytes (holomorphic Epichloë spp. and anamorphic Neotyphodium spp.) are systemic, often heritable symbionts of cool-season grasses (subfamily Pooideae). Many epichloae provide protection to their hosts by producing anti-insect compounds. Among these are the loline alkaloids (LA), which are toxic and deterrent to a broad range of herbivorous insects but not to mammalian herbivores. LOL, a gene cluster containing nine genes, is associated with LA biosynthesis. We investigated coordinate regulation between LOL-gene expression and LA production in minimal medium (MM) cultures of Neotyphodium uncinatum. Expression of all LOL genes significantly fit temporal quadratic patterns during LA production. LOL-gene expression started before LA were detectable, and increased while LA accumulated. The highest gene expression level was reached at close to the time of most rapid LA accumulation, and gene expression declined to a very low level as amounts of LA plateaued. Temporal expression profiles of the nine LOL genes were tightly correlated with each other, but not as tightly correlated with proC and metE (genes for biosynthesis of precursor amino acids). Furthermore, the start days and peak days of expression significantly correlated with the order of the LOL-cluster genes in the genome. Hierarchical cluster analysis indicated three pairs of genes-lolA and lolC, lolO and lolD, and lolT and lolE-expression of which was especially tightly correlated. Of these, lolA and lolC tended to be expressed early, and lolT and lolE tended to be expressed late, in keeping with the putative roles of the respective gene products in the LA-biosynthesis pathway. Several common transcriptional binding sites were discovered in the LOL upstream regions. However, low expression of P(lolC2)uidA and P(lolA2)uidA in N. uncinatum transformants suggested induced expression of LOL genes might be subject to position effect at the LOL locus.

  5. Global Warming.

    ERIC Educational Resources Information Center

    Hileman, Bette

    1989-01-01

    States the foundations of the theory of global warming. Describes methodologies used to measure the changes in the atmosphere. Discusses steps currently being taken in the United States and the world to slow the warming trend. Recognizes many sources for the warming and the possible effects on the earth. (MVL)

  6. Global Warming?

    ERIC Educational Resources Information Center

    Eichman, Julia Christensen; Brown, Jeff A.

    1994-01-01

    Presents information and data on an experiment designed to test whether different atmosphere compositions are affected by light and temperature during both cooling and heating. Although flawed, the experiment should help students appreciate the difficulties that researchers face when trying to find evidence of global warming. (PR)

  7. Global warming

    NASA Astrophysics Data System (ADS)

    Houghton, John

    2005-06-01

    'Global warming' is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of 'greenhouse gases', of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth's surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this warming are changes of climate. The basic science of the 'greenhouse effect' that leads to the warming is well understood. More detailed understanding relies on numerical models of the climate that integrate the basic dynamical and physical equations describing the complete climate system. Many of the likely characteristics of the resulting changes in climate (such as more frequent heat waves, increases in rainfall, increase in frequency and intensity of many extreme climate events) can be identified. Substantial uncertainties remain in knowledge of some of the feedbacks within the climate system (that affect the overall magnitude of change) and in much of the detail of likely regional change. Because of its negative impacts on human communities (including for instance substantial sea-level rise) and on ecosystems, global warming is the most important environmental problem the world faces. Adaptation to the inevitable impacts and mitigation to reduce their magnitude are both necessary. International action is being taken by the world's scientific and political communities. Because of the need for urgent action, the greatest challenge is to move rapidly to much increased energy efficiency and to non-fossil-fuel energy sources.

  8. Warm Up with Skill.

    ERIC Educational Resources Information Center

    Hoyle, R. J.; Smith, Robert F.

    1989-01-01

    Too little time is often spent on warm-up activities in the school or recreation class. Warm-ups are often perfunctory and unimaginative. Several suggestions are made for warm-up activities that incorporate both previously learned and new skills, while preparing the body for more vigorous activity. (IAH)

  9. Warm autoimmune hemolytic anemia.

    PubMed

    Naik, Rakhi

    2015-06-01

    Warm autoimmune hemolytic anemia (AIHA) is defined as the destruction of circulating red blood cells (RBCs) in the setting of anti-RBC autoantibodies that optimally react at 37°C. The pathophysiology of disease involves phagocytosis of autoantibody-coated RBCs in the spleen and complement-mediated hemolysis. Thus far, treatment is aimed at decreasing autoantibody production with immunosuppression or reducing phagocytosis of affected cells in the spleen. The role of complement inhibitors in warm AIHA has not been explored. This article addresses the diagnosis, etiology, and treatment of warm AIHA and highlights the role of complement in disease pathology.

  10. Warm and Cool Dinosaurs.

    ERIC Educational Resources Information Center

    Mannlein, Sally

    2001-01-01

    Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of warm and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)

  11. Draft global warming study

    SciTech Connect

    Not Available

    1990-01-01

    The 1990 Resource Program Global Warming Study examines potential Bonneville Power Administration (BPA) resource alternatives related to the risk of global warming. The study evaluates strategies for reducing net carbon emissions, and identifies the net carbon contribution of certain resource strategies designed to reduce those emissions. Carbon dioxide (CO{sub 2}) is the greenhouse gas'' most associated with electricity production. The main purpose of the global warming study is to identify possible courses of action that BPA might take to reduce its contributions to the risk of global warming and to estimate the efficacy and costs of each approach. The principal measure of effectiveness is the reduction in total atmospheric carbon emissions compared to a base case. 13 refs., 2 tabs.

  12. Reconciling Warming Trends

    NASA Technical Reports Server (NTRS)

    Schmidt, Gavin A.; Shindell, Drew T.; Tsigaridis, Konstantinos

    2014-01-01

    Climate models projected stronger warming over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El NiNo evolution, may explain most of the discrepancy.

  13. Warm Hands and Feet

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Comfort Products, Inc. was responsible for the cold weather glove and thermal boots, adapted from a spacesuit design that kept astronauts warm or cool in the temperature extremes of the Apollo Moon Mission. Gloves and boots are thermally heated. Batteries are worn inside wrist of glove or sealed in sole of skiboot and are rechargeable hundreds of times. They operate flexible resistance circuit which is turned on periodically when wearer wants to be warm.

  14. Polar Warming Drivers

    NASA Astrophysics Data System (ADS)

    McDunn, T. L.; Bougher, S. W.; Mischna, M. A.; Murphy, J. R.

    2012-12-01

    Polar warming is a dynamically induced temperature enhancement over mid-to-high latitudes that results in a reversed (poleward) meridional temperature gradient. This phenomenon was recently characterized over the 40-90 km altitude region [1] based on nearly three martian years of Mars Climate Sounder observations [2, 3]. Here we investigate which forcing mechanisms affect the magnitude and distribution of the observed polar warming by conducting simulations with the Mars Weather Research and Forecasting General Circulation Model [4, 5]. We present simulations confirming the influence topography [6] and dust loading [e.g., 7] have upon polar warming. We then present simulations illustrating the modulating influence gravity wave momentum deposition exerts upon polar warming, consistent with previous modeling studies [e.g., 8]. The results of this investigation suggest the magnitude and distribution of polar warming in the martian middle atmosphere is modified by gravity wave activity and that the characteristics of the gravity waves that most significantly affect polar warming vary with season. References: [1] McDunn, et al., 2012 (JGR), [2]Kleinböhl, et al., 2009 (JGR), [3] Kleinböhl, et al., 2011 (JQSRT), [4] Richardson, et al., 2007 (JGR), [5] Mischna, et al., 2011 (Planet. Space Sci.), [6] Richardson and Wilson, 2002 (Nature), [7] Haberle, et al., 1982 (Icarus), [8] Barnes, 1990 (JGR).

  15. Warm up to the idea: Global warming is here

    SciTech Connect

    Lynch, C.F.

    1996-07-01

    This article summarizes recent information about global warming as well as the history of greenhouse gas emissions which have lead to more and more evidence of global warming. The primary source detailed is the second major study report on global warming by the Intergovernmental Panel on climate change. Along with comments about the environmental effects of global warming such as coastline submersion, the economic, social and political aspects of alleviating greenhouse emissions and the threat of global warming are discussed.

  16. Long range global warming

    SciTech Connect

    Rolle, K.C.; Pulkrabek, W.W.; Fiedler, R.A.

    1995-12-31

    This paper explores one of the causes of global warming that is often overlooked, the direct heating of the environment by engineering systems. Most research and studies of global warming concentrate on the modification that is occurring to atmospheric air as a result of pollution gases being added by various systems; i.e., refrigerants, nitrogen oxides, ozone, hydrocarbons, halon, and others. This modification affects the thermal radiation balance between earth, sun and space, resulting in a decrease of radiation outflow and a slow rise in the earth`s steady state temperature. For this reason the solution to the problem is perceived as one of cleaning up the processes and effluents that are discharged into the environment. In this paper arguments are presented that suggest, that there is a far more serious cause for global warming that will manifest itself in the next two or three centuries; direct heating from the exponential growth of energy usage by humankind. Because this is a minor contributor to the global warming problem at present, it is overlooked or ignored. Energy use from the combustion of fuels and from the output of nuclear reactions eventually is manifest as warming of the surroundings. Thus, as energy is used at an ever increasing rate the consequent global warming also increases at an ever increasing rate. Eventually this rate will become equal to a few percent of solar radiation. When this happens the earth`s temperature will have risen by several degrees with catastrophic results. The trends in world energy use are reviewed and some mathematical models are presented to suggest future scenarios. These models can be used to predict when the global warming problem will become undeniably apparent, when it will become critical, and when it will become catastrophic.

  17. Model predicts global warming

    NASA Astrophysics Data System (ADS)

    Wainger, Lisa A.

    Global greenhouse warming will be clearly identifiable by the 1990s, according to eight scientists who have been studying climate changes using computer models. Researchers at NASA's Goddard Space Flight Center, Goddard Institute for Space Studies, New York, and the Massachusetts Institute of Technology, Cambridge, say that by the 2010s, most of the globe will be experiencing “substantial” warming. The level of warming will depend on amounts of trace gases, or greenhouse gases, in the atmosphere.Predictions for the next 70 years are based on computer simulations of Earth's climate. In three runs of the model, James Hansen and his colleagues looked at the effects of changing amounts of atmospheric gases with time.

  18. Warm and Cool Cityscapes

    ERIC Educational Resources Information Center

    Jubelirer, Shelly

    2012-01-01

    Painting cityscapes is a great way to teach first-grade students about warm and cool colors. Before the painting begins, the author and her class have an in-depth discussion about big cities and what types of buildings or structures that might be seen in them. They talk about large apartment and condo buildings, skyscrapers, art museums,…

  19. -induced continental warming

    NASA Astrophysics Data System (ADS)

    Kamae, Youichi; Watanabe, Masahiro; Kimoto, Masahide; Shiogama, Hideo

    2014-11-01

    In this the second of a two-part study, we examine the physical mechanisms responsible for the increasing contrast of the land-sea surface air temperature (SAT) in summertime over the Far East, as observed in recent decades and revealed in future climate projections obtained from a series of transient warming and sensitivity experiments conducted under the umbrella of the Coupled Model Intercomparison Project phase 5. On a global perspective, a strengthening of land-sea SAT contrast in the transient warming simulations of coupled atmosphere-ocean general circulation models is attributed to an increase in sea surface temperature (SST). However, in boreal summer, the strengthened contrast over the Far East is reproduced only by increasing atmospheric CO2 concentration. In response to SST increase alone, the tropospheric warming over the interior of the mid- to high-latitude continents including Eurasia are weaker than those over the surrounding oceans, leading to a weakening of the land-sea SAT contrast over the Far East. Thus, the increasing contrast and associated change in atmospheric circulation over East Asia is explained by CO2-induced continental warming. The degree of strengthening of the land-sea SAT contrast varies in different transient warming scenarios, but is reproduced through a combination of the CO2-induced positive and SST-induced negative contributions to the land-sea contrast. These results imply that changes of climate patterns over the land-ocean boundary regions are sensitive to future scenarios of CO2 concentration pathways including extreme cases.

  20. Teaching Global Warming

    NASA Astrophysics Data System (ADS)

    Hobson, Art

    2004-05-01

    Every citizen's education should include socially relevant science courses because, as the American Association for the Advancement of Science puts it, "Without a scientifically literate population, the outlook for a better world is not promising." I have developed a conceptual liberal-arts physics course that covers the major principles of classical physics, emphasizes modern/contemporary physics, and includes societal topics such as global warming, ozone depletion, transportation, exponential growth, scientific methodology, risk assessment, nuclear weapons, nuclear power, and the energy future. The societal topics, occupying only about 15% of the class time, appear to be the main cause of the surprising popularity of this course among non-scientists. I will outline some ideas for incorporating global warming into such a course or into any other introductory physics course. For further details, see my textbook Physics: Concepts and Connections (Prentice Hall, 3rd edition 2003).

  1. Warm Little Inflaton

    NASA Astrophysics Data System (ADS)

    Bastero-Gil, Mar; Berera, Arjun; Ramos, Rudnei O.; Rosa, João G.

    2016-10-01

    We show that inflation can naturally occur at a finite temperature T >H that is sustained by dissipative effects, when the inflaton field corresponds to a pseudo Nambu-Goldstone boson of a broken gauge symmetry. Similar to the Little Higgs scenarios for electroweak symmetry breaking, the flatness of the inflaton potential is protected against both quadratic divergences and the leading thermal corrections. We show that, nevertheless, nonlocal dissipative effects are naturally present and are able to sustain a nearly thermal bath of light particles despite the accelerated expansion of the Universe. As an example, we discuss the dynamics of chaotic warm inflation with a quartic potential and show that the associated observational predictions are in very good agreement with the latest Planck results. This model constitutes the first realization of warm inflation requiring only a small number of fields; in particular, the inflaton is directly coupled to just two light fields.

  2. Global Warming And Meltwater

    NASA Astrophysics Data System (ADS)

    Bratu, S.

    2012-04-01

    In order to find new approaches and new ideas for my students to appreciate the importance of science in their daily life, I proposed a theme for them to debate. They had to search for global warming information and illustrations in the media, and discuss the articles they found in the classroom. This task inspired them to search for new information about this important and timely theme in science. I informed my students that all the best information about global warming and meltwater they found would be used in a poster that would help us to update the knowledge base of the Physics laboratory. I guided them to choose the most eloquent images and significant information. Searching and working to create this poster, the students arrived to better appreciate the importance of science in their daily life and to critically evaluate scientific information transmitted via the media. In the poster we created, one can find images, photos and diagrams and some interesting information: Global warming refers to the rising average temperature of the Earth's atmosphere and oceans and its projected evolution. In the last 100 years, the Earth's average surface temperature increased by about 0.8 °C with about two thirds of the increase occurring over just the last three decades. Warming of the climate system is unequivocal, and scientists are more than 90% certain most of it is caused by increasing concentrations of greenhouse gases produced by human activities such as deforestation and burning fossil fuel. They indicate that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C for the lowest emissions scenario and 2.4 to 6.4 °C for the highest predictions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, and potentially result in expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing decrease of

  3. Warm hilltop inflation

    SciTech Connect

    Sanchez, Juan Carlos Bueno; Dimopoulos, Konstantinos; Bastero-Gil, Mar; Berera, Arjun

    2008-06-15

    We study the low-temperature limit of warm inflation in a hilltop model. This limit remains valid up to the end of inflation, allowing an analytic description of the entire inflationary stage. In the weak dissipative regime, if the kinetic density of the inflaton dominates after inflation, low-scale inflation is attained with Hubble scale as low as 1 GeV. In the strong dissipative regime, the model satisfies the observational requirements for the spectral index with a mild tuning of the model parameters, while also overcoming the {eta}-problem of inflation. However, there is some danger of gravitino overproduction unless the particle content of the theory is large.

  4. FLATs: Warming Up - continuation

    NASA Astrophysics Data System (ADS)

    Calzetti, Daniela

    1997-07-01

    The purpose of this proposal is to monitor the flat fields during the interval between the end of science observations and the exhaustion of cryogen and subsequent warming of the dewar to > 100K. These flats will provide a monitor for particulate comtamination {GROT} and detector lateral position {from the coronagraphic spot and FDA vignetting}. They will provide some measure of relative {flat field} and absolute QE variation as a function of temperature. When stars are visible they might provide a limited degree of focus determination.

  5. FLATs: Warming Up

    NASA Astrophysics Data System (ADS)

    Calzetti, Daniela

    1997-07-01

    The purpose of this proposal is to monitor the flat fields during the interval between the end of science observations and the exhaustion of cryogen and subsequent warming of the dewar to > 100K. These flats will provide a monitor for particulate comtamination {GROT} and detector lateral position {from the coronagraphic spot and FDA vignetting}. They will provide some measure of relative {flat field} and absolute QE variation as a function of temperature. When stars are visible they might provide a limited degree of focus determination.

  6. Is Global Warming Accelerating?

    NASA Astrophysics Data System (ADS)

    Shukla, J.; Delsole, T. M.; Tippett, M. K.

    2009-12-01

    A global pattern that fluctuates naturally on decadal time scales is identified in climate simulations and observations. This newly discovered component, called the Global Multidecadal Oscillation (GMO), is related to the Atlantic Meridional Oscillation and shown to account for a substantial fraction of decadal fluctuations in the observed global average sea surface temperature. IPCC-class climate models generally underestimate the variance of the GMO, and hence underestimate the decadal fluctuations due to this component of natural variability. Decomposing observed sea surface temperature into a component due to anthropogenic and natural radiative forcing plus the GMO, reveals that most multidecadal fluctuations in the observed global average sea surface temperature can be accounted for by these two components alone. The fact that the GMO varies naturally on multidecadal time scales implies that it can be predicted with some skill on decadal time scales, which provides a scientific rationale for decadal predictions. Furthermore, the GMO is shown to account for about half of the warming in the last 25 years and hence a substantial fraction of the recent acceleration in the rate of increase in global average sea surface temperature. Nevertheless, in terms of the global average “well-observed” sea surface temperature, the GMO can account for only about 0.1° C in transient, decadal-scale fluctuations, not the century-long 1° C warming that has been observed during the twentieth century.

  7. Warm Inflation Model Building

    NASA Astrophysics Data System (ADS)

    Bastero-Gil, Mar; Berera, Arjun

    We review the main aspects of the warm inflation scenario, focusing on the inflationary dynamics and the predictions related to the primordial spectrum of perturbations, to be compared with the recent cosmological observations. We study in detail three different classes of inflationary models, chaotic, hybrid models and hilltop models, and discuss their embedding into supersymmetric models and the consequences for model building of the warm inflationary dynamics based on first principles calculations. Due to the extra friction term introduced in the inflaton background evolution generated by the dissipative dynamics, inflation can take place generically for smaller values of the field, and larger values of couplings and masses. When the dissipative dynamics dominates over the expansion, in the so-called strong dissipative regime, inflation proceeds with sub-Planckian inflaton values. Models can be naturally embedded into a supergravity framework, with SUGRA corrections suppressed by the Planck mass now under control, for a larger class of Kähler potentials. In particular, this provides a simpler solution to the "eta" problem in supersymmetric hybrid inflation, without restricting the Kähler potentials compatible with inflation. For chaotic models dissipation leads to a smaller prediction for the tensor-to-scalar ratio and a less tilted spectrum when compared to the cold inflation scenario. We find in particular that a small component of dissipation renders the quartic model now consistent with the current CMB data.

  8. RHIC warm-bore systems

    SciTech Connect

    Welch, K.M.

    1994-07-01

    Pressure profiles, in time, are calculated as a consequence of anticipated outgassing of various beam components (e.g., rf cavities, etc.) and warm-bore beam pipes. Gold beam lifetimes and transverse beam emittance growth are given for calculated average pressures. Examples of undesirable warm-bore conditions are presented such as contaminated experimental beam pipes and warm-bore magnets (i.e., DX). These examples may prove instructive. The methods used in making these calculations are presented in Section 2. They are applicable to all linear systems. The calculations given apply to the RHIC accelerator and more specifically to warm-bore regions of the machine.

  9. Warm waters, bleached corals

    SciTech Connect

    Roberts, L.

    1990-10-12

    Two researchers, Tom Goreau of the Discovery Laboratory in Jamaica and Raymond Hayes of Howard University, claim that they have evidence that nearly clinches the temperature connection to the bleached corals in the Caribbean and that the coral bleaching is an indication of Greenhouse warming. The incidents of scattered bleaching of corals, which have been reported for decades, are increasing in both intensity and frequency. The researchers based their theory on increased temperature of the seas measured by satellites. However, some other scientists feel that the satellites measure the temperature of only the top few millimeters of the water and that since corals lie on reefs perhaps 60 to 100 feet below the ocean surface, the elevated temperatures are not significant.

  10. Global warming challenge

    SciTech Connect

    Hengeveld, H. )

    1994-11-01

    Global warming will necessitate significant adjustments in Canadian society and its economy. In 1979, the Canadian federal government created its Canadian Climate Program (CCP) in collaboration with other agencies, institutions, and individuals. It sought to coordinate national efforts to understand global and regional climate, and to promote better use of the emerging knowledge. Much of the CCP-coordinated research into sources and sinks of greenhouse gases interfaces with other national and international programs. Other researchers have become involved in the Northern Wetlands Study, a cooperative United States-Canada initiative to understand the role of huge northern bogs and muskegs in the carbon cycle. Because of the need to understand how the whole, linked climate system works, climate modeling emerged as a key focus of current research. 35 refs., 4 figs.

  11. Global Warming on Triton

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; Buie, M. W.; Pasachoff, J. M.; Babcock, B. A.; McConnochie, T. H.

    1998-01-01

    Triton, Neptune's largest moon, has been predicted to undergo significant seasonal changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global warming since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto.

  12. Diffuse, Warm Ionized Gas

    NASA Astrophysics Data System (ADS)

    Haffner, L. M.

    2002-05-01

    Over the past decade, new high-sensitivity observations have significantly advanced our knowledge of the diffuse, ionized gas in spiral galaxies. This component of the interstellar medium, often referred to as Warm Ionized Medium (WIM) or Diffuse Ionized Gas (DIG), plays an important role in the complex stellar-interstellar matter and energy cycle. In examining the distribution and physical properties of this gas, we learn not only about the conditions of the medium but also about processes providing heating and ionization in the halos of spiral galaxies. For the Milky Way, three new Hα surveys are available providing large sky coverage, arc-minute spatial resolution, and the ability to kinematically resolve this prominent optical emission line. These new, global views show that the Warm Ionized Medium of the Galaxy is ubiquitous as previously suspected, is rich with filamentary structure down to current resolution limits, and can be traced into the halo at large distances from the Galactic plane. Observations of additional optical emission lines are beginning to probe the physical conditions of the WIM. Early results suggest variations in the temperature and ionization state of the gas which are not adequately explained by Lyman continuum stellar photoionization alone. In parallel with this intensive work in the Milky Way have been numerous studies about the diffuse, ionized gas in other spiral galaxies. Here, deep, face-on spiral investigations provide some of the best maps of the global DIG distribution in a galaxy and begin to allow a probe of the local link between star formation and the powering of ionized gas. In addition, ionized gas has been traced out to impressive distances (z > 3 kpc) in edge-on spirals, revealing out large-scale changes in the physical conditions and kinematics of galactic halos.

  13. Interacting warm dark matter

    SciTech Connect

    Cruz, Norman; Palma, Guillermo; Zambrano, David; Avelino, Arturo E-mail: guillermo.palma@usach.cl E-mail: avelino@fisica.ugto.mx

    2013-05-01

    We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear λρ{sub m}{sup α}ρ{sub e}{sup β} form, where ρ{sub m} and ρ{sub e} are the energy densities of the dark matter and dark energy, respectively. The parameters α and β are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (λ,α,β) as well as w{sub m} and w{sub e} of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a warm dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a warm dark matter – phantom dark energy model without interaction, as well as by the ΛCDM model. We find also a large dispersion on the best estimated values of the (λ,α,β) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used.

  14. Local warming: daily temperature change influences belief in global warming.

    PubMed

    Li, Ye; Johnson, Eric J; Zaval, Lisa

    2011-04-01

    Although people are quite aware of global warming, their beliefs about it may be malleable; specifically, their beliefs may be constructed in response to questions about global warming. Beliefs may reflect irrelevant but salient information, such as the current day's temperature. This replacement of a more complex, less easily accessed judgment with a simple, more accessible one is known as attribute substitution. In three studies, we asked residents of the United States and Australia to report their opinions about global warming and whether the temperature on the day of the study was warmer or cooler than usual. Respondents who thought that day was warmer than usual believed more in and had greater concern about global warming than did respondents who thought that day was colder than usual. They also donated more money to a global-warming charity if they thought that day seemed warmer than usual. We used instrumental variable regression to rule out some alternative explanations.

  15. Defining Sudden Stratospheric Warmings

    NASA Astrophysics Data System (ADS)

    Butler, Amy; Seidel, Dian; Hardiman, Steven; Butchart, Neal; Birner, Thomas; Match, Aaron

    2015-04-01

    The general form of the definition for Sudden Stratospheric Warmings (SSWs) is largely agreed to be a reversal of the temperature gradient and of the zonal circulation polewards of 60° latitude at the 10 hPa level, as developed by the World Meteorological Organization (WMO) in the 1960s and 1970s. However, the details of the definition and its calculation are ambiguous, resulting in inconsistent classifications of SSW events. These discrepancies are problematic for understanding the observed frequency and statistical relationships with SSWs, and for maintaining a robust metric with which to assess wintertime stratospheric variability in observations and climate models. To provide a basis for community-wide discussion, we examine how the SSW definition has changed over time and how sensitive the detection of SSWs is to the definition used. We argue that the general form of the SSW definition should be clarified to ensure that it serves current research and forecasting purposes, and propose possible ways to update the definition.

  16. Warm dense crystallography

    NASA Astrophysics Data System (ADS)

    Valenza, Ryan A.; Seidler, Gerald T.

    2016-03-01

    The intense femtosecond-scale pulses from x-ray free electron lasers (XFELs) are able to create and interrogate interesting states of matter characterized by long-lived nonequilibrium semicore or core electron occupancies or by the heating of dense phases via the relaxation cascade initiated by the photoelectric effect. We address here the latter case of "warm dense matter" (WDM) and investigate the observable consequences of x-ray heating of the electronic degrees of freedom in crystalline systems. We report temperature-dependent density functional theory calculations for the x-ray diffraction from crystalline LiF, graphite, diamond, and Be. We find testable, strong signatures of condensed-phase effects that emphasize the importance of wide-angle scattering to study nonequilibrium states. These results also suggest that the reorganization of the valence electron density at eV-scale temperatures presents a confounding factor to achieving atomic resolution in macromolecular serial femtosecond crystallography (SFX) studies at XFELs, as performed under the "diffract before destroy" paradigm.

  17. Warming up for Planck

    SciTech Connect

    Bartrum, Sam; Berera, Arjun; Rosa, João G. E-mail: ab@ph.ed.ac.uk

    2013-06-01

    The recent Planck results and future releases on the horizon present a key opportunity to address a fundamental question in inflationary cosmology of whether primordial density perturbations have a quantum or thermal origin, i.e. whether particle production may have significant effects during inflation. Warm inflation provides a natural arena to address this issue, with interactions between the scalar inflaton and other degrees of freedom leading to dissipative entropy production and associated thermal fluctuations. In this context, we present relations between CMB observables that can be directly tested against observational data. In particular, we show that the presence of a thermal bath warmer than the Hubble scale during inflation decreases the tensor-to-scalar ratio with respect to the conventional prediction in supercooled inflation, yielding r < 8|n{sub t}|, where n{sub t} is the tensor spectral index. Focusing on supersymmetric models at low temperatures, we determine consistency relations between the observables characterizing the spectrum of adiabatic scalar and tensor modes, both for generic potentials and particular canonical examples, and which we compare with the WMAP and Planck results. Finally, we include the possibility of producing the observed baryon asymmetry during inflation through dissipative effects, thereby generating baryon isocurvature modes that can be easily accommodated by the Planck data.

  18. Recent warming of lake Kivu.

    PubMed

    Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  19. Recent Warming of Lake Kivu

    PubMed Central

    Katsev, Sergei; Aaberg, Arthur A.; Crowe, Sean A.; Hecky, Robert E.

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730

  20. Delayed flowering and global warming

    NASA Astrophysics Data System (ADS)

    Cook, B. I.; Wolkovich, E. M.; Parmesan, C.

    2011-12-01

    Within general trends toward earlier spring, observed cases of species and ecosystems that have not advanced their phenology, or have even delayed it, appear paradoxical, especially when made in temperate regions experiencing significant warming. The typical interpretation of this pattern has been that non-responders are insensitive to relatively small levels of warming over the past 40 years, while species showing delays are often viewed as statistical noise or evidence for unknown confounding factors at play. However, plant physiology studies suggest that when winter chilling (vernalization) is required to initiate spring development, winter warming may retard spring events, masking expected advances caused by spring warming. Here, we analyzed long-term data on phenology and seasonal temperatures from 490 species on two continents and demonstrate that 1) apparent non-responders are indeed responding to warming, but their responses to winter and spring warming are opposite in sign, 2) observed trends in first flowering date depend strongly on the magnitude of a given species' response to autumn/winter versus spring warming, and 3) inclusion of these effects strongly improves hindcast predictions of long-term flowering trends. With a few notable exceptions, climate change research has focused on the overall mean trend towards phenological advance, minimizing discussion of apparently non-responding species. Our results illuminate an under-studied source of complexity in wild species responses and support the need for models incorporating diverse environmental cues in order to improve predictability of species responses to anthropogenic climate change.

  1. Amplified Arctic warming by phytoplankton under greenhouse warming

    PubMed Central

    Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho

    2015-01-01

    Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical–ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean−atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes. PMID:25902494

  2. Amplified Arctic warming by phytoplankton under greenhouse warming.

    PubMed

    Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho

    2015-05-12

    Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical-ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean-atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes.

  3. Weird Warm Spot on Exoplanet

    NASA Video Gallery

    This animation illustrates an unexpected warm spot on the surface of a gaseous exoplanet. NASA's Spitzer Space Telescope discovered that the hottest part of the planet, shown here as bright, orange...

  4. The Great Warming Brian Fagan

    NASA Astrophysics Data System (ADS)

    Fagan, B. M.

    2010-12-01

    The Great Warming is a journey back to the world of a thousand years ago, to the Medieval Warm Period. Five centuries of irregular warming from 800 to 1250 had beneficial effects in Europe and the North Atlantic, but brought prolonged droughts to much of the Americas and lands affected by the South Asian monsoon. The book describes these impacts of warming on medieval European societies, as well as the Norse and the Inuit of the far north, then analyzes the impact of harsh, lengthy droughts on hunting societies in western North America and the Ancestral Pueblo farmers of Chaco Canyon, New Mexico. These peoples reacted to drought by relocating entire communities. The Maya civilization was much more vulnerable that small-scale hunter-gatherer societies and subsistence farmers in North America. Maya rulers created huge water storage facilities, but their civilization partially collapsed under the stress of repeated multiyear droughts, while the Chimu lords of coastal Peru adapted with sophisticated irrigation works. The climatic villain was prolonged, cool La Niñalike conditions in the Pacific, which caused droughts from Venezuela to East Asia, and as far west as East Africa. The Great Warming argues that the warm centuries brought savage drought to much of humanity, from China to Peru. It also argues that drought is one of the most dangerous elements in today’s humanly created global warming, often ignored by preoccupied commentators, but with the potential to cause over a billion people to starve. Finally, I use the book to discuss the issues and problems of communicating multidisciplinary science to the general public.

  5. How warm days increase belief in global warming

    NASA Astrophysics Data System (ADS)

    Zaval, Lisa; Keenan, Elizabeth A.; Johnson, Eric J.; Weber, Elke U.

    2014-02-01

    Climate change judgements can depend on whether today seems warmer or colder than usual, termed the local warming effect. Although previous research has demonstrated that this effect occurs, studies have yet to explain why or how temperature abnormalities influence global warming attitudes. A better understanding of the underlying psychology of this effect can help explain the public's reaction to climate change and inform approaches used to communicate the phenomenon. Across five studies, we find evidence of attribute substitution, whereby individuals use less relevant but available information (for example, today's temperature) in place of more diagnostic but less accessible information (for example, global climate change patterns) when making judgements. Moreover, we rule out alternative hypotheses involving climate change labelling and lay mental models. Ultimately, we show that present temperature abnormalities are given undue weight and lead to an overestimation of the frequency of similar past events, thereby increasing belief in and concern for global warming.

  6. Distinguishing warming-induced drought from drought-induced warming

    NASA Astrophysics Data System (ADS)

    Roderick, M. L.; Yin, D.

    2015-12-01

    It is usually observed that temperatures, especially maximum temperatures are higher during drought. A very widely held public perception is that the increase in temperature is a cause of drought. This represents the warming-induced drought scenario. However, the agricultural and hydrologic scientific communities have a very different interpretation with drought being the cause of increasing temperature. In essence, those communities assume the warming is a surface feedback and their interpretation is for drought-induced warming. This is a classic cause-effect problem that has resisted definitive explanation due to the lack of radiative observations at suitable spatial and temporal scales. In this presentation we first summarise the observations and then use theory to untangle the cause-effect relationships that underlie the competing interpretations. We then show how satellite data (CERES, NASA) can be used to disentangle the cause-effect relations.

  7. Analysis of data from spacecraft (stratospheric warmings)

    NASA Technical Reports Server (NTRS)

    Anderson, A. D.

    1974-01-01

    Links between the upper atmosphere and the stratosphere were studied to explain stratospheric warmings, and to correlate the warmings with other terrestrial and solar phenomena. Physical mechanisms for warming, or which may act as a trigger are discussed along with solar and geophysical indices. Two stratospheric warming cases are analyzed.

  8. Active Movement Warm-Up Routines

    ERIC Educational Resources Information Center

    Walter, Teri; Quint, Ashleigh; Fischer, Kim; Kiger, Joy

    2011-01-01

    This article presents warm-ups that are designed to physiologically and psychologically prepare students for vigorous physical activity. An active movement warm-up routine is made up of three parts: (1) active warm-up movement exercises, (2) general preparation, and (3) the energy system. These warm-up routines can be used with all grade levels…

  9. Global warming and infectious disease.

    PubMed

    Khasnis, Atul A; Nettleman, Mary D

    2005-01-01

    Global warming has serious implications for all aspects of human life, including infectious diseases. The effect of global warming depends on the complex interaction between the human host population and the causative infectious agent. From the human standpoint, changes in the environment may trigger human migration, causing disease patterns to shift. Crop failures and famine may reduce host resistance to infections. Disease transmission may be enhanced through the scarcity and contamination of potable water sources. Importantly, significant economic and political stresses may damage the existing public health infrastructure, leaving mankind poorly prepared for unexpected epidemics. Global warming will certainly affect the abundance and distribution of disease vectors. Altitudes that are currently too cool to sustain vectors will become more conducive to them. Some vector populations may expand into new geographic areas, whereas others may disappear. Malaria, dengue, plague, and viruses causing encephalitic syndromes are among the many vector-borne diseases likely to be affected. Some models suggest that vector-borne diseases will become more common as the earth warms, although caution is needed in interpreting these predictions. Clearly, global warming will cause changes in the epidemiology of infectious diseases. The ability of mankind to react or adapt is dependent upon the magnitude and speed of the change. The outcome will also depend on our ability to recognize epidemics early, to contain them effectively, to provide appropriate treatment, and to commit resources to prevention and research.

  10. Warming early Earth and Mars

    SciTech Connect

    Kasting, J.F.

    1997-05-23

    Sagan and Chyba, in their article on page 1217 of this issue, have revived an old debate about how liquid water was maintained on early Earth and Mars despite a solar luminosity 25 to 30% lower than that at present. A theory that has been popular for some time is that greatly elevated concentrations of atmospheric COD produced by the action of the carbonate-silicate cycle, provided enough of a greenhouse effect to warm early Earth. However, Rye et al. have placed geochemical constraints on early atmospheric CO{sub 2} abundances that fall well below the levels needed to warm the surface. These constraints are based on the absence of siderite (FeCO{sub 3}) in ancient soil profiles-a negative and, hence, rather weak form of evidence- and apply to the time period 2.2 to 2.8 billion years ago, when Earth was already middle aged. Nonetheless, the soil data provide some indication that atmospheric CO{sub 2} levels may have been lower than previously thought. An even more serious problem arises if one tries to keep early Mars warm with CO{sub 2}. Model calculations predict that CO{sub 2} clouds would form on Mars in the upper troposphere, reducing the lapse rate and severely limiting the amount of surface warming. A suggestion that CO{sub 2} clouds may have warmed the planet radiatively has yet to be borne out by detailed calculations. 26 refs.

  11. Global warming: trends and effects.

    PubMed

    Tickell, C

    1993-01-01

    As animals we have been a remarkably successful species; but also as animals we are vulnerable to environmental, in particular climate change. Such change is accelerating as a result of human activity, and global warming may already be taking place. Although we can foresee the trends, we cannot yet be specific about the results. Change usually proceeds by steps rather than gradients. But warming would probably include new risks to human health and contribute to an increase in human displacement. Of course climate change is only one among other complex problems facing human society, but it is closely related to them all, including population increase, environmental degradation and loss of biodiversity. We cannot prevent global warming but we can anticipate and mitigate some of its worst effects. Peoples and governments still need persuading of the need for action and of the magnitude of the issue at stake.

  12. Cosmic Rays and Global Warming

    SciTech Connect

    Sloan, T.; Wolfendale, A. W.

    2008-01-24

    Some workers have claimed that the observed temporal correlations of (low level) terrestrial cloud cover with the cosmic ray intensity changes, due to solar modulation, are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim in some detail. So far, we have not found any evidence in support and so our conclusions are to doubt it. From the absence of corroborative evidence we estimate that less than 15% at the 95% confidence level, of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 43 years is due to this cause. The origin of the correlation itself is probably the cycle of solar irradiance although there is, as yet, no certainty.

  13. Global Warming: Physics and Facts

    SciTech Connect

    Levi, B.G.; Hafemeister, D.; Scribner, R.

    1992-05-01

    This report contains papers on: A tutorial on global atmospheric energetics and the greenhouse effect; global climate models: what and how; comparison of general circulation models; climate and the earth`s radiation budget; temperature and sea level change; short-term climate variability and predictions; the great ocean conveyor; trace gases in the atmosphere: temporal and spatial trends; the geochemical carbon cycle and the uptake of fossil fuel CO{sub 2}; forestry and global warming; the physical and policy linkages; policy implications of greenhouse warming; options for lowering US carbon dioxide emissions; options for reducing carbon dioxide emissions; and science and diplomacy: a new partnership to protect the environment.

  14. Global Warming: Physics and Facts

    SciTech Connect

    Levi, B.G. ); Hafemeister, D. , Washington, DC ); Scribner, R. )

    1992-01-01

    This report contains papers on: A tutorial on global atmospheric energetics and the greenhouse effect; global climate models: what and how; comparison of general circulation models; climate and the earth's radiation budget; temperature and sea level change; short-term climate variability and predictions; the great ocean conveyor; trace gases in the atmosphere: temporal and spatial trends; the geochemical carbon cycle and the uptake of fossil fuel CO{sub 2}; forestry and global warming; the physical and policy linkages; policy implications of greenhouse warming; options for lowering US carbon dioxide emissions; options for reducing carbon dioxide emissions; and science and diplomacy: a new partnership to protect the environment.

  15. Global warming at the summit

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    During the recent summit meeting between Russian President Vladimir Putin and U.S. President Bill Clinton, the two leaders reaffirmed their concerns about global warming and the need to continue to take actions to try to reduce the threat.In a June 4 joint statement, they stressed the need to develop flexibility mechanisms, including international emissions trading, under the Kyoto Protocol to the United Nations Framework Convention on Climate Change. They also noted that initiatives to reduce the risk of greenhouse warming, including specific mechanisms of the Kyoto Protocol, could potentially promote economic growth.

  16. Warming up to solar energy

    SciTech Connect

    Biondo, B.

    1996-07-01

    Increasingly alarmed by threats to their financial security posed by an escalating number of weather-related catastrophes, major insurance companaies, particularly those in Europe and Asia, are starting to support a variety of measures that would slowe the production of grenhouse gases worlwide. As the insurance and banking industries turn their attention to global warming, investments in solar energy take on growing appeal.

  17. Equatorial refuge amid tropical warming

    NASA Astrophysics Data System (ADS)

    Karnauskas, Kristopher B.; Cohen, Anne L.

    2012-07-01

    Upwelling across the tropical Pacific Ocean is projected to weaken in accordance with a reduction of the atmospheric overturning circulation, enhancing the increase in sea surface temperature relative to other regions in response to greenhouse-gas forcing. In the central Pacific, home to one of the largest marine protected areas and fishery regions in the global tropics, sea surface temperatures are projected to increase by 2.8°C by the end of this century. Of critical concern is that marine protected areas may not provide refuge from the anticipated rate of large-scale warming, which could exceed the evolutionary capacity of coral and their symbionts to adapt. Combining high-resolution satellite measurements, an ensemble of global climate models and an eddy-resolving regional ocean circulation model, we show that warming and productivity decline around select Pacific islands will be mitigated by enhanced upwelling associated with a strengthening of the equatorial undercurrent. Enhanced topographic upwelling will act as a negative feedback, locally mitigating the surface warming. At the Gilbert Islands, the rate of warming will be reduced by 0.7+/-0.3°C or 25+/-9% per century, or an overall cooling effect comparable to the local anomaly for a typical El Niño, by the end of this century. As the equatorial undercurrent is dynamically constrained to the Equator, only a handful of coral reefs stand to benefit from this equatorial island effect. Nevertheless, those that do face a lower rate of warming, conferring a significant advantage over neighbouring reef systems. If realized, these predictions help to identify potential refuges for coral reef communities from anticipated climate changes of the twenty-first century.

  18. Isolating Stratospheric Warmings -- Mesosphere to Troposphere

    NASA Astrophysics Data System (ADS)

    Coughlin, K.

    Stratospheric Warming events exhibit the most drastic changes seen in the stratosphere and yet the categorization of these events continues to be adhoc Understandably the definitions of major warming minor warmings and or Canadian warmings often depend on the scientific problem at hand And yet we show here that these events are statistically separated from the rest of the days in the winter stratosphere We show how warmings can be isolated and defined in a objective manner Furthermore we are then able to show the effect of these warmings from the mesosphere down to the troposphere

  19. Warming trends: Adapting to nonlinear change

    SciTech Connect

    Jonko, Alexandra K.

    2015-01-28

    As atmospheric carbon dioxide concentrations rise, some regions are expected to warm more than others. Research suggests that whether warming will intensify or slow down over time also depends on location.

  20. Trophic mismatch requires seasonal heterogeneity of warming.

    PubMed

    Straile, Dietmar; Kerimoglu, Onur; Peeters, Frank

    2015-10-01

    Climate warming has been shown to advance the phenology of species. Asynchronous changes in phenology between interacting species may disrupt feeding interactions (phenological mismatch), which could have tremendous consequences for ecosystem functioning. Long-term field observations have suggested asynchronous shifts in phenology with warming, whereas experimental studies have not been conclusive. Using proxy-based modeling of three trophic levels (algae, herbivores, and fish), we .show that asynchronous changes in phenology only occur if warming is seasonally heterogeneous, but not if warming is constant throughout the year. If warming is seasonally heterogeneous, the degree and even direction of asynchrony depends on the specific seasonality of the warming. Conclusions about phenological mismatches in food web interactions may therefore produce controversial results if the analyses do not distinguish between seasonally constant and seasonal specific warming. Furthermore, our results suggest that predicting asynchrony between interacting species requires reliable warming predictions that resolve sub-seasonal time scales. PMID:26649399

  1. Arctic climate change: Greenhouse warming unleashed

    NASA Astrophysics Data System (ADS)

    Mauritsen, Thorsten

    2016-04-01

    Human activity alters the atmospheric composition, which leads to global warming. Model simulations suggest that reductions in emission of sulfur dioxide from Europe since the 1970s could have unveiled rapid Arctic greenhouse gas warming.

  2. Multidecadal warming of Antarctic waters.

    PubMed

    Schmidtko, Sunke; Heywood, Karen J; Thompson, Andrew F; Aoki, Shigeru

    2014-12-01

    Decadal trends in the properties of seawater adjacent to Antarctica are poorly known, and the mechanisms responsible for such changes are uncertain. Antarctic ice sheet mass loss is largely driven by ice shelf basal melt, which is influenced by ocean-ice interactions and has been correlated with Antarctic Continental Shelf Bottom Water (ASBW) temperature. We document the spatial distribution of long-term large-scale trends in temperature, salinity, and core depth over the Antarctic continental shelf and slope. Warming at the seabed in the Bellingshausen and Amundsen seas is linked to increased heat content and to a shoaling of the mid-depth temperature maximum over the continental slope, allowing warmer, saltier water greater access to the shelf in recent years. Regions of ASBW warming are those exhibiting increased ice shelf melt. PMID:25477461

  3. Hydrological consequences of global warming

    SciTech Connect

    Miller, Norman L.

    2009-06-01

    The 2007 Intergovernmental Panel for Climate Change indicates there is strong evidence that the atmospheric concentration of carbon dioxide far exceeds the natural range over the last 650,000 years, and this recent warming of the climate system is unequivocal, resulting in more frequent extreme precipitation events, earlier snowmelt runoff, increased winter flood likelihoods, increased and widespread melting of snow and ice, longer and more widespread droughts, and rising sea level. The effects of recent warming has been well documented and climate model projections indicate a range of hydrological impacts with likely to very likely probabilities (67 to 99 percent) of occurring with significant to severe consequences in response to a warmer lower atmosphere with an accelerating hydrologic cycle.

  4. Solar trends and global warming

    NASA Astrophysics Data System (ADS)

    Benestad, R. E.; Schmidt, G. A.

    2009-07-01

    We use a suite of global climate model simulations for the 20th century to assess the contribution of solar forcing to the past trends in the global mean temperature. In particular, we examine how robust different published methodologies are at detecting and attributing solar-related climate change in the presence of intrinsic climate variability and multiple forcings. We demonstrate that naive application of linear analytical methods such as regression gives nonrobust results. We also demonstrate that the methodologies used by Scafetta and West (2005, 2006a, 2006b, 2007, 2008) are not robust to these same factors and that their error bars are significantly larger than reported. Our analysis shows that the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980.

  5. MCCB warm adjustment testing concept

    NASA Astrophysics Data System (ADS)

    Erdei, Z.; Horgos, M.; Grib, A.; Preradović, D. M.; Rodic, V.

    2016-08-01

    This paper presents an experimental investigation in to operating of thermal protection device behavior from an MCCB (Molded Case Circuit Breaker). One of the main functions of the circuit breaker is to assure protection for the circuits where mounted in for possible overloads of the circuit. The tripping mechanism for the overload protection is based on a bimetal movement during a specific time frame. This movement needs to be controlled and as a solution to control this movement we choose the warm adjustment concept. This concept is meant to improve process capability control and final output. The warm adjustment device design will create a unique adjustment of the bimetal position for each individual breaker, determined when the testing current will flow thru a phase which needs to trip in a certain amount of time. This time is predetermined due to scientific calculation for all standard types of amperages and complies with the IEC 60497 standard requirements.

  6. Lagrangian description of warm plasmas

    NASA Technical Reports Server (NTRS)

    Kim, H.

    1970-01-01

    Efforts are described to extend the averaged Lagrangian method of describing small signal wave propagation and nonlinear wave interaction, developed by earlier workers for cold plasmas, to the more general conditions of warm collisionless plasmas, and to demonstrate particularly the effectiveness of the method in analyzing wave-wave interactions. The theory is developed for both the microscopic description and the hydrodynamic approximation to plasma behavior. First, a microscopic Lagrangian is formulated rigorously, and expanded in terms of perturbations about equilibrium. Two methods are then described for deriving a hydrodynamic Lagrangian. In the first of these, the Lagrangian is obtained by velocity integration of the exact microscopic Lagrangian. In the second, the expanded hydrodynamic Lagrangian is obtained directly from the expanded microscopic Lagrangian. As applications of the microscopic Lagrangian, the small-signal dispersion relations and the coupled mode equations are derived for all possible waves in a warm infinite, weakly inhomogeneous magnetoplasma, and their interactions are examined.

  7. The heated debate. [Global warming

    SciTech Connect

    Balling, R.C. Jr.

    1992-01-01

    The Heated Debate challenges head on the popular vision' of anthropogenically-caused global warming as characterized by catastrophic sea level rise, drought-desiccated farmlands, and more frequent and intense hurricanes spinning up and out from warmer tropical seas. The message of this book is that apocalyptic devastation of natural ecosystems and human socio-economic systems will not necessarily follow from a mild warming of earth's climate. According to Balling, the specter of apocalypse is clearly the dominant view held by scientists, decisionmakers and the public specter of apocalypse is clearly the dominant view held by scientists, decisionmakers and the public at large, and, in his view, it is just as clearly incorrect based on a careful examination of the historical evidence. The Heated Debate present the other side' of global warming; a kinder, gentler greenhouse debate, the stated purpose of the book is to provide the reader with some background to the greenhouse issue, present an analysis of the certainties and uncertainties for future climate change, and examine the most probably changes in climate that may occur as the greenhouse gases increase in concentration. Ultimately the author hopes the book will more completely inform decisionmakers so that they do not commit money and resources to what may turn out to be a non-problem. Indeed, global warming may have many more benefits than costs, and, in any event, the (climate) penalty for postponing action a few years is potentially small, while our knowledge base will increase tremendously allowing society to make wiser and more informed decisions.

  8. Economic Theory and Global Warming

    NASA Astrophysics Data System (ADS)

    Uzawa, Hirofumi

    2003-08-01

    Hirofumi Uzawa's theoretical framework addresses three major problems concerning global warming and other environmental hazards. First, it considers all phenomena involved with global environmental issues that exhibit externalities of one kind or another. Secondly, it covers global environmental issues involving international and intergenerational equity and justice. Lastly, it deals with global environmental issues concerning the management of the atmosphere, the oceans, water, soil, and other natural resources having to be decided by a consensus of affected countries.

  9. Analysis of data from spacecraft (stratospheric warmings)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The details of the stratospheric warming processes as to time, area, and intensity were established, and the warmings with other terrestrial and solar phenomena occurring at satellite platform altitudes, or observable from satellite platforms, were correlated. Links were sought between the perturbed upper atmosphere (mesosphere and thermosphere) and the stratosphere that might explain stratospheric warmings.

  10. Warm Dense Matter: An Overview

    SciTech Connect

    Kalantar, D H; Lee, R W; Molitoris, J D

    2004-04-21

    This document provides a summary of the ''LLNL Workshop on Extreme States of Materials: Warm Dense Matter to NIF'' which was held on 20, 21, and 22 February 2002 at the Wente Conference Center in Livermore, CA. The warm dense matter regime, the transitional phase space region between cold material and hot plasma, is presently poorly understood. The drive to understand the nature of matter in this regime is sparking scientific activity worldwide. In addition to pure scientific interest, finite temperature dense matter occurs in the regimes of interest to the SSMP (Stockpile Stewardship Materials Program). So that obtaining a better understanding of WDM is important to performing effective experiments at, e.g., NIF, a primary mission of LLNL. At this workshop we examined current experimental and theoretical work performed at, and in conjunction with, LLNL to focus future activities and define our role in this rapidly emerging research area. On the experimental front LLNL plays a leading role in three of the five relevant areas and has the opportunity to become a major player in the other two. Discussion at the workshop indicated that the path forward for the experimental efforts at LLNL were two fold: First, we are doing reasonable baseline work at SPLs, HE, and High Energy Lasers with more effort encouraged. Second, we need to plan effectively for the next evolution in large scale facilities, both laser (NIF) and Light/Beam sources (LCLS/TESLA and GSI) Theoretically, LLNL has major research advantages in areas as diverse as the thermochemical approach to warm dense matter equations of state to first principles molecular dynamics simulations. However, it was clear that there is much work to be done theoretically to understand warm dense matter. Further, there is a need for a close collaboration between the generation of verifiable experimental data that can provide benchmarks of both the experimental techniques and the theoretical capabilities. The conclusion of this

  11. Methods of Patient Warming during Abdominal Surgery

    PubMed Central

    Shao, Li; Zheng, Hong; Jia, Feng-Ju; Wang, Hui-Qin; Liu, Li; Sun, Qi; An, Meng-Ying; Zhang, Xiu-Hua; Wen, Hao

    2012-01-01

    Background Keeping abdominal surgery patients warm is common and warming methods are needed in power outages during natural disasters. We aimed to evaluate the efficacy of low-cost, low-power warming methods for maintaining normothermia in abdominal surgery patients. Methods Patients (n = 160) scheduled for elective abdominal surgery were included in this prospective clinical study. Five warming methods were applied: heated blood transfusion/fluid infusion vs. unheated; wrapping patients vs. not wrapping; applying moist dressings, heated or not; surgical field rinse heated or not; and applying heating blankets or not. Patients’ nasopharyngeal and rectal temperatures were recorded to evaluate warming efficacy. Significant differences were found in mean temperatures of warmed patients compared to those not warmed. Results When we compared temperatures of abdominal surgery patient groups receiving three specific warming methods with temperatures of control groups not receiving these methods, significant differences were revealed in temperatures maintained during the surgeries between the warmed groups and controls. Discussion The value of maintaining normothermia in patients undergoing abdominal surgery under general anesthesia is accepted. Three effective economical and practically applicable warming methods are combined body wrapping and heating blanket; combined body wrapping, heated moist dressings, and heating blanket; combined body wrapping, heated moist dressings, and warmed surgical rinse fluid, with or without heating blanket. These methods are practically applicable when low-cost method is indeed needed. PMID:22808045

  12. Cutaneous warming promotes sleep onset.

    PubMed

    Raymann, Roy J E M; Swaab, Dick F; Van Someren, Eus J W

    2005-06-01

    Sleep occurs in close relation to changes in body temperature. Both the monophasic sleep period in humans and the polyphasic sleep periods in rodents tend to be initiated when core body temperature is declining. This decline is mainly due to an increase in skin blood flow and consequently skin warming and heat loss. We have proposed that these intrinsically occurring changes in core and skin temperatures could modulate neuronal activity in sleep-regulating brain areas (Van Someren EJW, Chronobiol Int 17: 313-54, 2000). We here provide results compatible with this hypothesis. We obtained 144 sleep-onset latencies while directly manipulating core and skin temperatures within the comfortable range in eight healthy subjects under controlled conditions. The induction of a proximal skin temperature difference of only 0.78 +/- 0.03 degrees C (mean +/- SE) around a mean of 35.13 +/- 0.11 degrees C changed sleep-onset latency by 26%, i.e., by 3.09 minutes [95% confidence interval (CI), 1.91 to 4.28] around a mean of 11.85 min (CI, 9.74 to 14.41), with faster sleep onsets when the proximal skin was warmed. The reduction in sleep-onset latency occurred despite a small but significant decrease in subjective comfort during proximal skin warming. The induction of changes in core temperature (delta = 0.20 +/- 0.02 degrees C) and distal skin temperature (delta = 0.74 +/- 0.05 degrees C) were ineffective. Previous studies have demonstrated correlations between skin temperature and sleep-onset latency. Also, sleep disruption by ambient temperatures that activate thermoregulatory defense mechanisms has been shown. The present study is the first to experimentally demonstrate a causal contribution to sleep-onset latency of skin temperature manipulations within the normal nocturnal fluctuation range. Circadian and sleep-appetitive behavior-induced variations in skin temperature might act as an input signal to sleep-regulating systems. PMID:15677527

  13. High dissipative nonminimal warm inflation

    NASA Astrophysics Data System (ADS)

    Nozari, Kourosh; Shoukrani, Masoomeh

    2016-09-01

    We study a model of warm inflation in which both inflaton field and its derivatives are coupled nonminimally to curvature. We survey the spectrum of the primordial perturbations in high dissipative regime. By expanding the action up to the third order, the amplitude of the non-Gaussianity is studied both in the equilateral and orthogonal configurations. Finally, by adopting four sort of potentials, we compare our model with the Planck 2015 released observational data and obtain some constraints on the model's parameters space in the high dissipation regime.

  14. Warm/cold cloud processes

    NASA Technical Reports Server (NTRS)

    Bowdle, D. A.

    1979-01-01

    Technical assistance continued in support of the Atmospheric Cloud Physics Laboratory is discussed. A study of factors affecting warm cloud formation showed that the time of formation during an arbitrary expansion is independent of carrier gas composition for ideal gases and independent of aerosol concentration for low concentrations of very small aerosols. Equipment and procedures for gravimetric evaluation of a precision saturator were laboratory tested. A numerical feasibility study was conducted for the stable levitation of charged solution droplets by an electric field in a one-g static diffusion chamber. The concept, operating principles, applications, limits, and sensitivity of the levitation technique are discussed.

  15. Forecasting phenology under global warming.

    PubMed

    Ibáñez, Inés; Primack, Richard B; Miller-Rushing, Abraham J; Ellwood, Elizabeth; Higuchi, Hiroyoshi; Lee, Sang Don; Kobori, Hiromi; Silander, John A

    2010-10-12

    As a consequence of warming temperatures around the world, spring and autumn phenologies have been shifting, with corresponding changes in the length of the growing season. Our understanding of the spatial and interspecific variation of these changes, however, is limited. Not all species are responding similarly, and there is significant spatial variation in responses even within species. This spatial and interspecific variation complicates efforts to predict phenological responses to ongoing climate change, but must be incorporated in order to build reliable forecasts. Here, we use a long-term dataset (1953-2005) of plant phenological events in spring (flowering and leaf out) and autumn (leaf colouring and leaf fall) throughout Japan and South Korea to build forecasts that account for these sources of variability. Specifically, we used hierarchical models to incorporate the spatial variability in phenological responses to temperature to then forecast species' overall and site-specific responses to global warming. We found that for most species, spring phenology is advancing and autumn phenology is getting later, with the timing of events changing more quickly in autumn compared with the spring. Temporal trends and phenological responses to temperature in East Asia contrasted with results from comparable studies in Europe, where spring events are changing more rapidly than are autumn events. Our results emphasize the need to study multiple species at many sites to understand and forecast regional changes in phenology. PMID:20819816

  16. Population growth and global warming.

    PubMed

    Short, R V

    2009-01-01

    When I was born in 1930, the human population of the world was a mere 2 billion. Today, it has already reached 6.8 billion, and is projected to reach 9.1 billion by 2050. That is unsustainable. It is slowly beginning to dawn on us that Global Warming is the result of increasing human CO2 emissions, and the more people there are in the world, the worse it will become. Ultimately, it is the sky that will prove to be the limit to our numbers. The developed countries of the world are the most affluent, and also the most effluent, so we must lead by example and contain our own population growth and per capita emissions. We also have a big debt to repay to former colonial territories in Africa, Asia and South America, who desperately need our help to contain their excessive rates of population growth. Belgian and Dutch obstetricians and gynaecologists can play a critical role in this endeavour. After all, we already have a pill that will stop global warming - the oral contraceptive pill. PMID:25478068

  17. Population growth and global warming.

    PubMed

    Short, R V

    2009-01-01

    When I was born in 1930, the human population of the world was a mere 2 billion. Today, it has already reached 6.8 billion, and is projected to reach 9.1 billion by 2050. That is unsustainable. It is slowly beginning to dawn on us that Global Warming is the result of increasing human CO2 emissions, and the more people there are in the world, the worse it will become. Ultimately, it is the sky that will prove to be the limit to our numbers. The developed countries of the world are the most affluent, and also the most effluent, so we must lead by example and contain our own population growth and per capita emissions. We also have a big debt to repay to former colonial territories in Africa, Asia and South America, who desperately need our help to contain their excessive rates of population growth. Belgian and Dutch obstetricians and gynaecologists can play a critical role in this endeavour. After all, we already have a pill that will stop global warming - the oral contraceptive pill.

  18. Rapid endovascular warming for profound hypothermia.

    PubMed

    Laniewicz, Megan; Lyn-Kew, Kenneth; Silbergleit, Robert

    2008-02-01

    Profound hypothermia is associated with high mortality and morbidity. Optimal outcomes have been reported with invasive extracorporeal warming techniques not readily available in most hospitals. Endovascular warming devices may provide a less invasive alternative. A 68-year-old woman developed profound hypothermia after environmental exposure. On arrival, she was comatose, severely bradycardic, without palpable pulses, and with a core body temperature of 23.0 degrees C (72 degrees F). Attempts to warm her with traditional methods during 2 hours were ineffective. An endovascular temperature control system was placed and effectively warmed the patient at about 3 degrees C (4.5 degrees F) per hour, with return of hemodynamic stability. When hypothermia is profound, surface warming works poorly and invasive strategies, including cardiopulmonary bypass, are recommended. Rapid warming from profound hypothermia can be accomplished with endovascular systems, and these may be an effective alternative to more invasive extracorporeal methods. PMID:17681640

  19. Global warming; What needs to be done

    SciTech Connect

    Not Available

    1991-04-01

    This paper names global warming as a high-level risk. However, global warming's risk status is a point of debate in some circles, reflecting one of the complexities of using risk-based criteria to establish priorities for action. The position that global warming is a long-term environmental trend that must be halted. In this paper, argument son both sides of the global warming issue are presented to illustrate the difficulties associated with establishing the existence and magnitude of environmental and health risks, an issue that must be faced if the SAB recommendations for EPA policy change are implemented.

  20. Stratospheric sudden warming and lunar tide

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yosuke; Kosch, Michael

    2016-07-01

    A stratospheric sudden warming is a large-scale disturbance in the middle atmosphere. Recent studies have shown that the effect of stratospheric sudden warnings extends well into the upper atmosphere. A stratospheric sudden warming is often accompanied by an amplification of lunar tides in the ionosphere/theremosphere. However, there are occasionally winters when a stratospheric sudden warming occurs without an enhancement of the lunar tide in the upper atmosphere, and other winters when large lunar tides are observed without a strong stratospheric sudden warming. We examine the winters when the correlation breaks down and discuss possible causes.

  1. Modern Physics and Warm Friendship

    NASA Astrophysics Data System (ADS)

    Yang, Chen Ning

    2013-05-01

    During the academic year 1941-42 I was a senior in the Physics Department at the National Southwest Associated University in Kunming. The Department was quite small, with about 10 faculty members, 10 instructors, a few graduate students and not more than 20 students in each undergraduate class. When the academic year started in the fall of 1941, a new face appeared, auditing many of the senior and graduate courses and participating in all discussions. That was Huang Kun. He had already received his bachelor's degree in physics from Yenching University in Beiping, and had come to Kunming to join the Southwest Associated University as an instructor. Soon we got to know each other well, and that was the beginning of half of a century of warm friendship...

  2. How to stop global warming

    SciTech Connect

    Goldenberg, J. . Dept. de Fisica)

    1990-11-01

    This paper reports on how to stop global warming. At the Toronto Conference on Climate Change in 1988, the world's industrialized nations agreed on a goal of cutting greenhouse gas emissions 20 percent by the year 2005. This would not stabilize atmospheric levels of greenhouse gases but would at least slow their accumulation. Although difficult to achieve, the Toronto goal is certainly reachable. Newer, more efficient technologies can lower energy consumption without effecting economic output. CFC- substitutes can provide refrigeration. In fact, an international carbon tax of just $1 per barrel of oil, or $6 per ton of coal, would generate more than enough revenue to pay for the necessary fuel-saving measures. This tax could result from an international agreement similar to the 1987 Montreal Protocol, which obliges its signatories to cut down on production of CFCs.

  3. Meteorology: hurricanes and global warming.

    PubMed

    Landsea, Christopher W

    2005-12-22

    Anthropogenic climate change has the potential for slightly increasing the intensity of tropical cyclones through warming of sea surface temperatures. Emanuel has shown a striking and surprising association between sea surface temperatures and destructiveness by tropical cyclones in the Atlantic and western North Pacific basins. However, I question his analysis on the following grounds: it does not properly represent the observations described; the use of his Atlantic bias-removal scheme may not be warranted; and further investigation of a substantially longer time series for tropical cyclones affecting the continental United States does not show a tendency for increasing destructiveness. These factors indicate that instead of "unprecedented" tropical cyclone activity having occurred in recent years, hurricane intensity was equal or even greater during the last active period in the mid-twentieth century.

  4. End Calorimeter Warm Tube Heater

    SciTech Connect

    Primdahl, K.; /Fermilab

    1991-08-06

    The Tevatron accelerator beam tube must pass through the End Calorimeter cryostats of the D-Zero Collider Detector. Furthermore, the End Calorimeter cryostats must be allowed to roll back forty inches without interruption of the vacuum system; hence, the Tev tube must slide through the End Calorimeter cryostat as it is rolled back. The Tev pass through the End Calorimeter can actually be thought of as a cluster of concentric tubes: Tev tube, warm (vacuum vessel) tube, IS layers of superinsulation, cold tube (argon vessel), and Inner Hadronic center support tube. M. Foley generated an ANSYS model to study the heat load. to the cryostat. during collider physics studies; that is, without operation of the heater. A sketch of the model is included in the appendix. The vacuum space and superinsulation was modeled as a thermal solid, with conductivity derived from tests performed at Fermilab. An additional estimate was done. by this author, using data supplied by NR-2. a superinsulation manufacturer. The ANSYS result and hand calculation are in close agreement. The ANSYS model was modified. by this author. to incorporate the effect of the heater. Whereas the earlier model studied steady state operation only. the revised model considers the heater-off steady state mode as the initial condition. then performs a transient analysis with a final load step for time tending towards infinity. Results show the thermal gradient as a function of time and applied voltage. It should be noted that M. Foley's model was generated for one half the warm tube. implying the tube to be symmetric. In reality. the downstream connection (relative to the collision point) attachment to the vacuum shell is via several convolutions of a 0.020-inch wall bellows; hence. a nearly adiabatic boundary condition. Accordingly. the results reported in the table reflect extrapolation of the curves to the downstream end of the tube. Using results from the ANSYS analysis, that is, tube temperature and

  5. Liquid Cooling/Warming Garment

    NASA Technical Reports Server (NTRS)

    Koscheyev, Victor S.; Leon, Gloria R.; Dancisak, Michael J.

    2010-01-01

    The NASA liquid cooling/ventilating garment (LCVG) currently in use was developed over 40 years ago. With the commencement of a greater number of extra-vehicular activity (EVA) procedures with the construction of the International Space Station, problems of astronaut comfort, as well as the reduction of the consumption of energy, became more salient. A shortened liquid cooling/warming garment (SLCWG) has been developed based on physiological principles comparing the efficacy of heat transfer of different body zones; the capability of blood to deliver heat; individual muscle and fat body composition as a basis for individual thermal profiles to customize the zonal sections of the garment; and the development of shunts to minimize or redirect the cooling/warming loop for different environmental conditions, physical activity levels, and emergency situations. The SLCWG has been designed and completed, based on extensive testing in rest, exercise, and antiorthostatic conditions. It is more energy efficient than the LCVG currently used by NASA. The total length of tubing in the SLCWG is approximately 35 percent less and the weight decreased by 20 percent compared to the LCVG. The novel features of the innovation are: 1. The efficiency of the SLCWG to maintain thermal status under extreme changes in body surface temperatures while using significantly less tubing than the LCVG. 2. The construction of the garment based on physiological principles of heat transfer. 3. The identification of the body areas that are most efficient in heat transfer. 4. The inclusion of a hood as part of the garment. 5. The lesser consumption of energy.

  6. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    PubMed

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). PMID:25640748

  7. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    PubMed

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall).

  8. Warming: mechanism and latitude dependence

    NASA Astrophysics Data System (ADS)

    Barkin, Yury

    2010-05-01

    Introduction. In the work it is shown, that in present warming of climate of the Earth and in style of its display a fundamental role the mechanism of the forced swing and relative oscillations of eccentric core of the Earth and its mantle plays. Relative displacements of the centers of mass of the core and the mantle are dictated by the features of orbital motions of bodies of solar system and nonineriality of the Earth reference frame (or ot the mantle) at the motion of the Earth with respect to a baricenter of solar system and at rotation of the planet. As a result in relative translational displacements of the core and the mantle the frequencies characteristic for orbital motion of all bodies of solar system, and also their combination are shown. Methods of a space geodesy, gravimetry, geophysics, etc. unequivocally and clearly confirm phenomenon of drift of the center of mass of the Earth in define northern direction. This drift is characterized by the significant velocity in about 5 mm/yr. The unique opportunity of its explanation consists in the natural assumption of existence of the unidirectional relative displacement (drift) the center of mass of the core and the center of mass of the mantle of the Earth. And this displacement (at superfluous mass of the core in 16.7 % from the mass of full the Earth) is characterized still more significant velocity in 2.6 cm/yr and occurs on our geodynamic studies in a direction to Taimyr peninsula. The dynamic explanation to century drift for today does not exist. It is possible to note, however, that data of observations of last years, indirectly testifying that similar drifts of the centers of mass in present epoch occur on other bodies of Solar system have been obtain: the Sun, Mars, the Titan, Enceladus, the Neptune, etc. We connect with mentioned phenomena the observed secular variations of natural processes on this celestial bodies. I.e. it is possible to assume, that observable eccentric positions of the centers

  9. Efficient Warm-ups: Creating a Warm-up That Works.

    ERIC Educational Resources Information Center

    Lauffenburger, Sandra Kay

    1992-01-01

    Proper warm-up is important for any activity, but designing an effective warm-up can be time consuming. An alternative approach is to take a cue from Laban Movement Analysis (LMA) and consider movement design from the perspective of space and planes of motion. Efficient warm-up exercises using LMA are described. (SM)

  10. Nonlinear electron oscillations in a warm plasma

    SciTech Connect

    Sarkar, Anwesa; Maity, Chandan; Chakrabarti, Nikhil

    2013-12-15

    A class of nonstationary solutions for the nonlinear electron oscillations of a warm plasma are presented using a Lagrangian fluid description. The solution illustrates the nonlinear steepening of an initial Gaussian electron density disturbance and also shows collapse behavior in time. The obtained solution may indicate a class of nonlinear transient structures in an unmagnetized warm plasma.

  11. Warming of Water in a Glass

    ERIC Educational Resources Information Center

    Paulins, Paulis; Krauze, Armands; Ozolinsh, Maris; Muiznieks, Andris

    2016-01-01

    The article focuses on the process of water warming from 0 °C in a glass. An experiment is performed that analyzes the temperature in the top and bottom layers of water during warming. The experimental equipment is very simple and can be easily set up using devices available in schools. The temperature curves obtained from the experiment help us…

  12. Warm-up: A Psychophysiological Phenomenon.

    ERIC Educational Resources Information Center

    Lopez, Richard; Dausman, Cindy

    1981-01-01

    The effectiveness of warm-up as an aid to athletic performance is related to an interaction of both psychological and physiological factors. Benefits of warm-up include an increase in blood and muscle temperatures and an increased muscular endurance. (JN)

  13. Exploring the Sociopolitical Dimensions of Global Warming

    ERIC Educational Resources Information Center

    Sadler, Troy D.; Klosterman, Michelle L.

    2009-01-01

    The authors present an activity to help high school students conceptualize the sociopolitical complexity of global warming through an exploration of varied perspectives on the issue. They argue that socioscientific issues such as global warming present important contexts for learning science and that the social and political dimensions of these…

  14. Global Warming: Lessons from Ozone Depletion

    ERIC Educational Resources Information Center

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  15. Global Warming: Understanding and Teaching the Forecast.

    ERIC Educational Resources Information Center

    Andrews, Bill

    1994-01-01

    A resource for the teaching of the history and causes of climate change. Discusses evidence of climate change from the Viking era, early ice ages, the most recent ice age, natural causes of climate change, human-made causes of climate change, projections of global warming, and unequal warming. (LZ)

  16. Turkish Students' Ideas about Global Warming

    ERIC Educational Resources Information Center

    Kilinc, Ahmet; Stanisstreet, Martin; Boyes, Edward

    2008-01-01

    A questionnaire was used to explore the prevalence of ideas about global warming in Year 10 (age 15-16 years) school students in Turkey. The frequencies of individual scientific ideas and misconceptions about the causes, consequences and "cures" of global warming were identified. In addition, several general findings emerged from this study.…

  17. Rapid warming of Large Marine Ecosystems

    NASA Astrophysics Data System (ADS)

    Belkin, Igor M.

    2009-04-01

    The need to understand local effects of global climate change is most urgent in the Large Marine Ecosystems (LMEs) since marine ecosystem-based management requires information on the LME scale. Reported here is a study of sea surface temperature (SST) change in the World Ocean LMEs in 1957-2006 that revealed strong regional variations in the rate of SST change. The rapid warming in 1982-2006 was confined to the Subarctic Gyre, European Seas, and East Asian Seas. These LMEs warmed at rates 2-4 times the global mean rate. The most rapid warming was observed in the land-locked or semi-enclosed European and East Asian Seas (Baltic Sea, North Sea, Black Sea, Japan Sea/East Sea, and East China Sea) and also over the Newfoundland-Labrador Shelf. The Indian Ocean LMEs’ warming was slow, while two major upwelling areas - California and Humboldt Currents - experienced a slight cooling. The Subarctic Gyre warming was likely caused by natural variability related to the North Atlantic Oscillation. The extremely rapid surface warming in the enclosed and semi-enclosed European and East Asian Seas surrounded by major industrial/population agglomerations may have resulted from the observed terrestrial warming directly affecting the adjacent coastal seas. Regions of freshwater influence in the European and East Asian Seas seem to play a special role in modulating and exacerbating global warming effects on the regional scale.

  18. Global Warming: How Much and Why?

    ERIC Educational Resources Information Center

    Lanouette, William

    1990-01-01

    Summarizes the history of the study of global warming and includes a discussion of the role of gases, like carbon dioxide, methane, and chlorofluorocarbon (CFC). Discusses modern research on the global warming, including computer modelling and the super-greenhouse effect. (YP)

  19. Global Warming: Understanding and Teaching the Forecast.

    ERIC Educational Resources Information Center

    Andrews, Bill

    1995-01-01

    A resource for teaching about the consequences of global warming. Discusses feedback from the temperature increase, changes in the global precipitation pattern, effects on agriculture, weather extremes, effects on forests, effects on biodiversity, effects on sea levels, and actions which will help the global community cope with global warming. (LZ)

  20. Catching a Cold When It's Warm

    MedlinePlus

    ... our exit disclaimer . Subscribe Catching a Cold When It’s Warm What’s the Deal with Summertime Sniffles? Most ... be more unfair than catching a cold when it’s warm? How can cold symptoms arise when it’s ...

  1. Warm Disks from Giant Impacts

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    In the process of searching for exoplanetary systems, weve discovered tens of debris disks close around distant stars that are especially bright in infrared wavelengths. New research suggests that we might be looking at the late stages of terrestrial planet formation in these systems.Forming Terrestrial PlanetsAccording to the widely-accepted formation model for our solar-system, protoplanets the size of Mars formed within a protoplanetary disk around our Sun. Eventually, the depletion of the gas in the disk led the orbits of these protoplanets to become chaotically unstable. Finally, in the giant impact stage, many of the protoplanets collided with each other ultimately leading to the formation of the terrestrial planets and their moons as we know them today.If giant impact stages occur in exoplanetary systems, too leading to the formation of terrestrial exoplanets how would we detect this process? According to a study led by Hidenori Genda of the Tokyo Institute of Technology, we might be already be witnessing this stage in observations of warm debris disks around other stars. To test this, Genda and collaborators model giant impact stages and determine what we would expect to see from a system undergoing this violent evolution.Modeling CollisionsSnapshots of a giant impact in one of the authors simulations. The collision causes roughly 0.05 Earth masses of protoplanetary material to be ejected from the system. Click for a closer look! [Genda et al. 2015]The collaborators run a series of simulations evolving protoplanetary bodies in a solar system. The simulations begin 10 Myr into the lifetime of the solar system, i.e., after the gas from the protoplanetary disk has had time to be cleared and the protoplanetary orbits begin to destabilize. The simulations end when the protoplanets are done smashing into each other and have again settled into stable orbits, typically after ~100 Myr.The authors find that, over an average giant impact stage, the total amount of

  2. Global Warming: Lessons from Ozone Depletion

    NASA Astrophysics Data System (ADS)

    Hobson, Art

    2010-11-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of Arkansas have developed a conceptual understanding of energy and of electromagnetism, including the electromagnetic spectrum, I devote a lecture (and a textbook section) to ozone depletion and another lecture (and section) to global warming. Humankind came together in 1986 and quickly solved, to the extent that humans can solve it, ozone depletion. We could do the same with global warming, but we haven't and as yet there's no sign that we will. The parallel between the ozone and global warming cases, and the difference in outcomes, are striking and instructive.

  3. Eurasian Arctic abyssal waters are warming

    NASA Astrophysics Data System (ADS)

    Schauer, Ursula; von Appen, Wilken-Jon; Somavilla Cabrillo, Raquel; Behrendt, Axel; Rabe, Benjamin

    2016-04-01

    In the past decades, not only the upper water layers, but also the deepest layers of the Arctic Ocean have been warming. Observations show that the rate of warming varies markedly in the different basins with the fastest warming in the deep Greenland Sea (ca. 0.11°C per decade) and the Eurasian Basin featuring an average rate of ca. 0.01°C per decade. While the warming in the Greenland Sea is attributed to ongoing export of relatively warmer deep waters from the Arctic Ocean in combination with the halt of deep convection, the reason of Eurasian Basin deep warming is less clear. We discuss possible causes such as changes in the abyssal ventilation through slope convection, advection from other basins and/or geothermal heating through various sources.

  4. Global warming, insurance losses and financial industry

    SciTech Connect

    Low, N.C.

    1996-12-31

    Global warming causes extremely bad weather in the near term. They have already caught the attention of the insurance industry, as they suffered massive losses in the last decade. Twenty-one out of the 25 largest catastrophes in the US, mainly in the form of hurricanes have occurred in the last decade. The insurance industry has reacted by taking the risk of global warming in decisions as to pricing and underwriting decisions. But they have yet to take a more active role in regulating the factors that contributes to global warming. How global warming can impact the financial industry and the modern economy is explored. Insurance and modern financial derivatives are key to the efficient functioning of the modern economy, without which the global economy can still function but will take a giant step backward. Any risk as global warming that causes economic surprises will hamper the efficient working of the financial market and the modern economy.

  5. Global warming: The complete briefing

    SciTech Connect

    Houghton, J.

    1994-12-31

    John Houghton has drawn on the exhaustive efforts of the Intergovernmental Panel on Climate Change (IPCC) to produce a notably compact, impeccably complete and authoritative, meticulously balanced, and lucidly presented guide to the complex yet vital issue of global warming. Its subtitle is not mere hyperbole: this truly is a complete briefing. Certainly, one could not ask for a more authoritative brief: Houghton has led an imposing series of national and international efforts relating to climate, including the most recent scientific assessments of the IPCC. Citing many concrete examples, Houghton begins by convincing that climate truly is important to humankind and that climate is far from constant. He then elucidates the mechanisms that maintain the benign climate of our planet, providing in the process, for example, the most accurate explanation of the natural greenhouse effect that has yet appeared in print. He then treats the individual greenhouse gases responsible for maintaining the earth`s warmth and presents projections of their probable future concentrations as influenced by human activities. Further chapters deal with conclusions drawn from climate models, estimates of the impacts on human activities, and possible policies and actions to mitigate or alleviate the changes and their consequences.

  6. Global warming and reproductive health.

    PubMed

    Potts, Malcolm; Henderson, Courtney E

    2012-10-01

    The largest absolute numbers of maternal deaths occur among the 40-50 million women who deliver annually without a skilled birth attendant. Most of these deaths occur in countries with a total fertility rate of greater than 4. The combination of global warming and rapid population growth in the Sahel and parts of the Middle East poses a serious threat to reproductive health and to food security. Poverty, lack of resources, and rapid population growth make it unlikely that most women in these countries will have access to skilled birth attendants or emergency obstetric care in the foreseeable future. Three strategies can be implemented to improve women's health and reproductive rights in high-fertility, low-resource settings: (1) make family planning accessible and remove non-evidenced-based barriers to contraception; (2) scale up community distribution of misoprostol for prevention of postpartum hemorrhage and, where it is legal, for medical abortion; and (3) eliminate child marriage and invest in girls and young women, thereby reducing early childbearing.

  7. Thermal pollution causes global warming

    NASA Astrophysics Data System (ADS)

    Nordell, Bo

    2003-09-01

    Over longer time-scales there is no net heat inflow to Earth since incoming solar energy is re-emitted at exactly the same rate. To maintain Earth's thermal equilibrium, however, there must be a net outflow equal to the geothermal heat flow. Performed calculations show that the net heat outflow in 1880 was equal to the geothermal heat flow, which is the only natural net heat source on Earth. Since then, heat dissipation from the global use of nonrenewable energy sources has resulted in additional net heating. In, e.g. Sweden, which is a sparsely populated country, this net heating is about three times greater than the geothermal heat flow. Such thermal pollution contributes to global warming until the global temperature has reached a level where this heat is also emitted to space. Heat dissipation from the global use of fossil fuels and nuclear power is the main source of thermal pollution. Here, it was found that one third of current thermal pollution is emitted to space and that a further global temperature increase of 1.8 °C is required until Earth is again in thermal equilibrium.

  8. Some economics of global warming

    SciTech Connect

    Schelling, T.C. )

    1992-03-01

    The greenhouse effect itself is simple enough to understand and is not in any real dispute. What is in dispute is its magnitude over the coming century, its translation into changes in climates around the globe, and the impacts of those climate changes on human welfare and the natural environment. These are beyond the professional understanding of any single person. The sciences involved are too numerous and diverse. Demography, economics, biology, and the technology sciences are needed to project emissions; atmospheric chemistry, oceanography, biology, and meteorology are needed to translate emissions into climates; biology, agronomy, health sciences, economics, sociology, and glaciology are needed to identify and assess impacts on human societies and natural ecosystems. And those are not all. There are expert judgments on large pieces of the subject, but no single person clothed in this panoply of disciplines has shown up or is likely to. This article makes an attempt to forecast the economic and social consequences of global warming due to anthropogenic greenhouse gases, and attempting to prevent it.

  9. Global metabolic impacts of recent climate warming.

    PubMed

    Dillon, Michael E; Wang, George; Huey, Raymond B

    2010-10-01

    Documented shifts in geographical ranges, seasonal phenology, community interactions, genetics and extinctions have been attributed to recent global warming. Many such biotic shifts have been detected at mid- to high latitudes in the Northern Hemisphere-a latitudinal pattern that is expected because warming is fastest in these regions. In contrast, shifts in tropical regions are expected to be less marked because warming is less pronounced there. However, biotic impacts of warming are mediated through physiology, and metabolic rate, which is a fundamental measure of physiological activity and ecological impact, increases exponentially rather than linearly with temperature in ectotherms. Therefore, tropical ectotherms (with warm baseline temperatures) should experience larger absolute shifts in metabolic rate than the magnitude of tropical temperature change itself would suggest, but the impact of climate warming on metabolic rate has never been quantified on a global scale. Here we show that estimated changes in terrestrial metabolic rates in the tropics are large, are equivalent in magnitude to those in the north temperate-zone regions, and are in fact far greater than those in the Arctic, even though tropical temperature change has been relatively small. Because of temperature's nonlinear effects on metabolism, tropical organisms, which constitute much of Earth's biodiversity, should be profoundly affected by recent and projected climate warming.

  10. Relative roles of differential SST warming, uniform SST warming and land surface warming in determining the Walker circulation changes under global warming

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Li, Tim

    2016-04-01

    Most of CMIP5 models projected a weakened Walker circulation in tropical Pacific, but what causes such change is still an open question. By conducting idealized numerical simulations separating the effects of the spatially uniform sea surface temperature (SST) warming, extra land surface warming and differential SST warming, we demonstrate that the weakening of the Walker circulation is attributed to the western North Pacific (WNP) monsoon and South America land effects. The effect of the uniform SST warming is through so-called "richest-get-richer" mechanism. In response to a uniform surface warming, the WNP monsoon is enhanced by competing moisture with other large-scale convective branches. The strengthened WNP monsoon further induces surface westerlies in the equatorial western-central Pacific, weakening the Walker circulation. The increase of the greenhouse gases leads to a larger land surface warming than ocean surface. As a result, a greater thermal contrast occurs between American Continent and equatorial Pacific. The so-induced zonal pressure gradient anomaly forces low-level westerly anomalies over the equatorial eastern Pacific and weakens the Walker circulation. The differential SST warming also plays a role in driving low-level westerly anomalies over tropical Pacific. But such an effect involves a positive air-sea feedback that amplifies the weakening of both east-west SST gradient and Pacific trade winds.

  11. Climatic warming destabilizes forest ant communities

    PubMed Central

    Diamond, Sarah E.; Nichols, Lauren M.; Pelini, Shannon L.; Penick, Clint A.; Barber, Grace W.; Cahan, Sara Helms; Dunn, Robert R.; Ellison, Aaron M.; Sanders, Nathan J.; Gotelli, Nicholas J.

    2016-01-01

    How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America. At the community level, warming consistently increased occupancy of nests and decreased extinction and nest abandonment. This consistency was largely driven by strong responses of a subset of thermophilic species at each site. As colonies of thermophilic species persisted in nests for longer periods of time under warmer temperatures, turnover was diminished, and species interactions were likely altered. We found that dynamical (Lyapunov) community stability decreased with warming both within and between sites. These results refute null expectations of simple temperature-driven increases in the activity and movement of thermophilic ectotherms. The reduction in stability under warming contrasts with the findings of previous studies that suggest resilience of species interactions to experimental and natural warming. In the face of warmer, no-analog climates, communities of the future may become increasingly fragile and unstable.

  12. Global Warming Estimation from MSU

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, Robert; Yoo, Jung-Moon

    1998-01-01

    Microwave Sounding Unit (MSU) radiometer observations in Ch 2 (53.74 GHz) from sequential, sun-synchronous, polar-orbiting NOAA satellites contain small systematic errors. Some of these errors are time-dependent and some are time-independent. Small errors in Ch 2 data of successive satellites arise from calibration differences. Also, successive NOAA satellites tend to have different Local Equatorial Crossing Times (LECT), which introduce differences in Ch 2 data due to the diurnal cycle. These two sources of systematic error are largely time independent. However, because of atmospheric drag, there can be a drift in the LECT of a given satellite, which introduces time-dependent systematic errors. One of these errors is due to the progressive chance in the diurnal cycle and the other is due to associated chances in instrument heating by the sun. In order to infer global temperature trend from the these MSU data, we have eliminated explicitly the time-independent systematic errors. Both of the time-dependent errors cannot be assessed from each satellite. For this reason, their cumulative effect on the global temperature trend is evaluated implicitly. Christy et al. (1998) (CSL). based on their method of analysis of the MSU Ch 2 data, infer a global temperature cooling trend (-0.046 K per decade) from 1979 to 1997, although their near nadir measurements yield near zero trend (0.003 K/decade). Utilising an independent method of analysis, we infer global temperature warmed by 0.12 +/- 0.06 C per decade from the observations of the MSU Ch 2 during the period 1980 to 1997.

  13. The gravitino problem in supersymmetric warm inflation

    SciTech Connect

    Sánchez, Juan C. Bueno; Bastero-Gil, Mar; Berera, Arjun; Dimopoulos, Konstantinos; Kohri, Kazunori E-mail: mbg@ugr.es E-mail: konst.dimopoulos@lancaster.ac.uk

    2011-03-01

    The warm inflation paradigm considers the continuous production of radiation during inflation due to dissipative effects. In its strong dissipation limit, warm inflation gives way to a radiation dominated Universe. High scale inflation then yields a high reheating temperature, which then poses a severe gravitino overproduction problem for the supersymmetric realisations of warm inflation. In this paper we show that, in a certain class of supersymmetric models, the dissipative dynamics of the inflaton is such that the field can avoid its complete decay after inflation. In some cases, the residual energy density stored in the inflaton field oscillations may come to dominate over the radiation bath at a later epoch. If the inflaton field finally decays much later than the onset of this matter dominated phase, the entropy produced from its decay may be sufficient to counteract the excess of gravitinos produced during the last stages of warm inflation.

  14. Revised projection of future greenhouse warming

    NASA Astrophysics Data System (ADS)

    Schlesinger, Michael E.; Jiang, Xingjian

    1991-03-01

    Recent projections of greenhouse warming to 2100 are broadened here to include a recently suggested lower temperature sensitivity Delta T(2x) = 0.5 C. All projections are also revised by prescribing a lower value for a key parameter of the simple ocean model Pi which indicates the warming of the polar ocean relative to the warming of the nonpolar ocean. It is found that, for any value of Delta T(2x), the atmospheric temperature increases more rapidly with time as a consequence of the reduction in Pi. It is also found that a delay of 10 yrs in initiating a 20-year transition from the IPCC (Intergovernmental Panel on Climate Change) 'business as usual' scenario to any other IPCC scenario has only a small effect on the projected warming in 2100, regardless of the value of Delta T(2x). This indicates that the penalty for a 10-yr delay is small.

  15. Chamberless residential warm air furnace design

    SciTech Connect

    Godfree, J.

    1996-07-01

    This brief paper is an introduction to the concept of designing residential warm air furnaces without combustion chambers. This is possible since some small burners do not require the thermal support of a combustion chamber to complete the combustion process.

  16. Carbon cycle: Global warming then and now

    NASA Astrophysics Data System (ADS)

    Stassen, Peter

    2016-04-01

    A rapid warming event 55.8 million years ago was caused by extensive carbon emissions. The rate of change of carbon and oxygen isotopes in marine shelf sediments suggests that carbon emission rates were much slower than anthropogenic emissions.

  17. Observational constraints on monomial warm inflation

    NASA Astrophysics Data System (ADS)

    Visinelli, Luca

    2016-07-01

    Warm inflation is, as of today, one of the best motivated mechanisms for explaining an early inflationary period. In this paper, we derive and analyze the current bounds on warm inflation with a monomial potential U propto phip, using the constraints from the PLANCK mission. In particular, we discuss the parameter space of the tensor-to-scalar ratio r and the potential coupling λ of the monomial warm inflation in terms of the number of e-folds. We obtain that the theoretical tensor-to-scalar ratio r ~ 10‑8 is much smaller than the current observational constrain r lesssim 0.12, despite a relatively large value of the field excursion Δ phi ~ 0.1MPl. Warm inflation thus eludes the Lyth bound set on the tensor-to-scalar ratio by the field excursion.

  18. Global temperatures and the global warming ``debate''

    NASA Astrophysics Data System (ADS)

    Aubrecht, Gordon

    2009-04-01

    Many ordinary citizens listen to pronouncements on talk radio casting doubt on anthropogenic global warming. Some op-ed columnists likewise cast doubts, and are read by credulous citizens. For example, on 8 March 2009, the Boston Globe published a column by Jeff Jacoby, ``Where's global warming?'' According to Jacoby, ``But it isn't such hints of a planetary warming trend that have been piling up in profusion lately. Just the opposite.'' He goes on to write, ``the science of climate change is not nearly as important as the religion of climate change,'' and blamed Al Gore for getting his mistaken views accepted. George Will at the Washington Post also expressed denial. As a result, 44% of U.S. voters, according to the January 19 2009 Rasmussen Report, blame long-term planetary trends for global warming, not human beings. Is there global cooling, as skeptics claim? We examine the temperature record.

  19. Should we be concerned about global warming?

    PubMed

    Diaz, James H

    2006-01-01

    Accurate scientific predictions of the true human health outcomes of global climate change are significantly confounded by several effect modifiers that cannot be adjusted for analytically. Nevertheless, with the documented increase in average global surface temperature of 0.6 C. since 1975, there is uniform consensus in the international scientific community that the earth is warming from a variety of climatic effects, including cyclical re-warming and the cascading effects of greenhouse gas emissions to support human activities.

  20. Global warming: a vicious circle.

    PubMed

    Sinclair, J

    1991-01-01

    The problem of global warming (GW) is larger than it was originally suspected. The release of carbon dioxide (CO2), methane (ME), and nitrous oxide (NO2) by the activities of humans will do more than simply raise the global temperature. It will also trigger a variety of feedback loops that will accelerate the GW process. The extent of these feedback loops is currently impossible to incorporate into the computer models because they are not fully understood. But, from what we do know, it is clear that reductions in greenhouse gas (GG) emissions must be halted immediately. We are already committed to regional droughts, storms, water shortages, fishery disruptions and plant and animal extinctions. But the response of the oceans, forest, and ice masses has not yet been incorporated into our predictions. Almost all the feedbacks identified promise to increase GG concentrations. The carbon cycle is going to be affected in a variety of ways. Plants and soil store almost 3 times the CO2 as found in the atmosphere. Increased temperatures will increase plant respiration, thus increasing CO2 emissions. Forests will die, permafrost will melt and the result will be increased releases of CO2 and ME. The oceans and plankton can not absorb as much CO2 as the water temperature rises. At present levels GG concentrations will double by 2025. Thus scientists are calling for an immediate 60-80% reduction in CO2 and other GG emissions. It is up to the industrialized nations to solve this problem since they are the ones who created it. 75% of all human made CO2 comes from these countries. They also have the ability to help developing nations to do the same. 20 nations have already announced plans to stabilize or reduce their GG emissions, but it is attitudes and lifestyles that must be changed. This is the largest problem to ever face the human race and never before have we acted as we now must act in order to avoid a worldwide catastrophe.

  1. Global warming and nuclear power

    SciTech Connect

    Wood, L., LLNL

    1998-07-10

    -fold reduction might be attained. Even the first such halving of carbon intensivity of stationary-source energy production world-wide might permit continued slow power-demand growth in the highly developed countries and rapid development of the other 80% of the world, both without active governmental suppression of fossil fuel usage - while also stabilizing carbon input-rates into the Earth`s atmosphere. The second two-fold reduction might obviate most global warming concerns.

  2. Is global warming harmful to health?

    PubMed

    Epstein, P R

    2000-08-01

    Projections from computer models predict that global warming will expand the incidence and distribution of many serious medical disorders. Global warming, aside from indirectly causing death by drowning or starvation, promotes by various means the emergence, resurgence, and spread of infectious diseases. This article addresses the health effects of global warming and disrupted climate patterns in detail. Among the greatest health concerns are diseases transmitted by mosquitoes, such as malaria, dengue fever, yellow fever, and several kinds of encephalitis. Such disorders are projected to become increasingly prevalent because their insect carriers are very sensitive to meteorological conditions. In addition, floods and droughts resulting from global warming can each help trigger outbreaks by creating breeding grounds for insects whose desiccated eggs remain viable and hatch in still water. Other effects of global warming on health include the growth of opportunist populations and the increase of the incidence of waterborne diseases because of lack of clean water. In view of this, several steps are cited in order to facilitate the successful management of the dangers of global warming.

  3. The importance of warm season warming to western U.S. streamflow changes

    USGS Publications Warehouse

    Das, T.; Pierce, D.W.; Cayan, D.R.; Vano, J.A.; Lettenmaier, D.P.

    2011-01-01

    Warm season climate warming will be a key driver of annual streamflow changes in four major river basins of the western U.S., as shown by hydrological model simulations using fixed precipitation and idealized seasonal temperature changes based on climate projections with SRES A2 forcing. Warm season (April-September) warming reduces streamflow throughout the year; streamflow declines both immediately and in the subsequent cool season. Cool season (October-March) warming, by contrast, increases streamflow immediately, partially compensating for streamflow reductions during the subsequent warm season. A uniform warm season warming of 3C drives a wide range of annual flow declines across the basins: 13.3%, 7.2%, 1.8%, and 3.6% in the Colorado, Columbia, Northern and Southern Sierra basins, respectively. The same warming applied during the cool season gives annual declines of only 3.5%, 1.7%, 2.1%, and 3.1%, respectively. Copyright 2011 by the American Geophysical Union.

  4. Warming shifts 'worming': effects of experimental warming on invasive earthworms in northern North America.

    PubMed

    Eisenhauer, Nico; Stefanski, Artur; Fisichelli, Nicholas A; Rice, Karen; Rich, Roy; Reich, Peter B

    2014-01-01

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm performance. We tested these hypotheses in a field warming experiment at two sites in Minnesota, USA by sampling earthworms in closed and open canopy in three temperature treatments in 2010 and 2012. Structural equation modeling revealed that detrimental warming effects on earthworm densities and biomass could indeed be partly explained by warming-induced reductions in SWC. The direction of warming effects depended on the current average SWC: warming had neutral to positive effects at high SWC, whereas the opposite was true at low SWC. Our results suggest that warming limits the invasion of earthworms in northern North America by causing less favorable soil abiotic conditions, unless warming is accompanied by increased and temporally even distributions of rainfall sufficient to offset greater water losses from higher evapotranspiration. PMID:25363633

  5. Warming shifts 'worming': effects of experimental warming on invasive earthworms in northern North America.

    PubMed

    Eisenhauer, Nico; Stefanski, Artur; Fisichelli, Nicholas A; Rice, Karen; Rich, Roy; Reich, Peter B

    2014-11-03

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm performance. We tested these hypotheses in a field warming experiment at two sites in Minnesota, USA by sampling earthworms in closed and open canopy in three temperature treatments in 2010 and 2012. Structural equation modeling revealed that detrimental warming effects on earthworm densities and biomass could indeed be partly explained by warming-induced reductions in SWC. The direction of warming effects depended on the current average SWC: warming had neutral to positive effects at high SWC, whereas the opposite was true at low SWC. Our results suggest that warming limits the invasion of earthworms in northern North America by causing less favorable soil abiotic conditions, unless warming is accompanied by increased and temporally even distributions of rainfall sufficient to offset greater water losses from higher evapotranspiration.

  6. Warming shifts `worming': effects of experimental warming on invasive earthworms in northern North America

    NASA Astrophysics Data System (ADS)

    Eisenhauer, Nico; Stefanski, Artur; Fisichelli, Nicholas A.; Rice, Karen; Rich, Roy; Reich, Peter B.

    2014-11-01

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm performance. We tested these hypotheses in a field warming experiment at two sites in Minnesota, USA by sampling earthworms in closed and open canopy in three temperature treatments in 2010 and 2012. Structural equation modeling revealed that detrimental warming effects on earthworm densities and biomass could indeed be partly explained by warming-induced reductions in SWC. The direction of warming effects depended on the current average SWC: warming had neutral to positive effects at high SWC, whereas the opposite was true at low SWC. Our results suggest that warming limits the invasion of earthworms in northern North America by causing less favorable soil abiotic conditions, unless warming is accompanied by increased and temporally even distributions of rainfall sufficient to offset greater water losses from higher evapotranspiration.

  7. Can Global Warming be Stopped?

    NASA Astrophysics Data System (ADS)

    Luria, M.

    2013-12-01

    Earlier this year, the CO2 levels exceeded the 400 ppm level and there is no sign that the 1-2 ppm annual increase is going to slow down. Concerns regarding the danger of global warming have been reported in numerous occasions for more than a generation, ever since CO2 levels reached the 350 ppm range in the mid 1980's. Nevertheless, all efforts to slow down the increase have showed little if any effect. Mobile sources, including surface and marine transportation and aviation, consist of 20% of the global CO2 emission. The only realistic way to reduce the mobile sources' CO2 signature is by improved fuel efficiency. However, any progress in this direction is more than compensated by continuous increased demand. Stationary sources, mostly electric power generation, are responsible for the bulk of the global CO2 emission. The measurements have shown, that the effect of an increase in renewable sources, like solar wind and geothermal, combined with conversion from coal to natural gas where possible, conservation and efficiency improvement, did not compensate the increased demand mostly in developing countries. Increased usage of nuclear energy can provide some relief in carbon emission but has the potential of even greater environmental hazard. A major decrease in carbon emission can be obtained by either significant reduction in the cost of non-carbon based energy sources or by of carbon sequestration. The most economical way to make a significant decrease in carbon emission is to apply carbon sequestration technology at large point sources that use coal. Worldwide there are about 10,000 major sources that burn >7 billion metric tons of coal which generate the equivalent of 30 trillion kwh. There is a limited experience in CO2 sequestration of such huge quantities of CO2, however, it is estimated that the cost would be US$ 0.01-0.1 per kwh. The cost of eliminating this quantity can be estimated at an average of 1.5 trillion dollars annually. The major emitters, US

  8. 21 CFR 864.9205 - Blood and plasma warming device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blood and plasma warming device. 864.9205 Section... Blood and Blood Products § 864.9205 Blood and plasma warming device. (a) Nonelectromagnetic blood or plasma warming device—(1) Identification. A nonelectromagnetic blood and plasma warming device is...

  9. 21 CFR 864.9205 - Blood and plasma warming device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Blood and plasma warming device. 864.9205 Section... Blood and Blood Products § 864.9205 Blood and plasma warming device. (a) Nonelectromagnetic blood or plasma warming device—(1) Identification. A nonelectromagnetic blood and plasma warming device is...

  10. 21 CFR 864.9205 - Blood and plasma warming device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Blood and plasma warming device. 864.9205 Section... Blood and Blood Products § 864.9205 Blood and plasma warming device. (a) Nonelectromagnetic blood or plasma warming device—(1) Identification. A nonelectromagnetic blood and plasma warming device is...

  11. 21 CFR 864.9205 - Blood and plasma warming device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Blood and plasma warming device. 864.9205 Section... Blood and Blood Products § 864.9205 Blood and plasma warming device. (a) Nonelectromagnetic blood or plasma warming device—(1) Identification. A nonelectromagnetic blood and plasma warming device is...

  12. 21 CFR 864.9205 - Blood and plasma warming device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Blood and plasma warming device. 864.9205 Section... Blood and Blood Products § 864.9205 Blood and plasma warming device. (a) Nonelectromagnetic blood or plasma warming device—(1) Identification. A nonelectromagnetic blood and plasma warming device is...

  13. Warm Absorber Diagnostics of AGN Dynamics

    NASA Astrophysics Data System (ADS)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  14. Global warming without global mean precipitation increase?

    PubMed

    Salzmann, Marc

    2016-06-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K(-1) decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge. PMID:27386558

  15. Warm Indian Ocean, Weak Asian Monsoon

    NASA Astrophysics Data System (ADS)

    Koll Roxy, Mathew; Ritika, Kapoor; Terray, Pascal; Murtugudde, Raghu; Ashok, Karumuri; Nath Goswami, Buphendra

    2015-04-01

    There are large uncertainties looming over the status and fate of the South Asian monsoon in a changing climate. Observations and climate models have suggested that anthropogenic warming in the past century has increased the moisture availability and the land-sea thermal contrast in the tropics, favoring an increase in monsoon rainfall. In contrast, we notice that South Asian subcontinent experienced a relatively subdued warming during this period. At the same time, the tropical Indian Ocean experienced a nearly monotonic warming, at a rate faster than the other tropical oceans. Using long-term observations and coupled model experiments, we suggest that the enhanced Indian Ocean warming along with the suppressed warming of the subcontinent weaken the land-sea thermal contrast throughout the troposphere, dampen the monsoon Hadley circulation, and reduce the rainfall over South Asia. As a result, the summer monsoon rainfall during 1901-2012 shows a significant weakening trend over South Asia, extending from Pakistan through central India to Bangladesh.

  16. Global warming without global mean precipitation increase?

    PubMed Central

    Salzmann, Marc

    2016-01-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K−1 decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge. PMID:27386558

  17. Global warming without global mean precipitation increase?

    PubMed

    Salzmann, Marc

    2016-06-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K(-1) decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge.

  18. Global Warming: Settled Science? Unsettled Media Debate??

    NASA Astrophysics Data System (ADS)

    Schneider, S. H.

    2007-12-01

    The Intergovernmental Panel on Climate Change recently assessed the approximate 0.75°C warming since 1850 as an "unequivocal" trend. This is very rare and strong language for scientists who often lead with their caveats, not with their concerns. Later, the same report says it is "very likely" (i.e.- greater that 90% chance) that most of the warming of the past several decades can be attributed to human activities, primarily greenhouse gas emissions. So far, the science sounds "settled". Furthermore, the IPCC, as well as many other national assessments, assigns very high confidence to projections of further warming, intensified tropical cyclones, more extremes of drought and flood, and melting mountain glaciers and arctic sea ice in the twenty-first century. Still sounds settled. However, the likely range of warming projected by IPCC to 2100 varies by a whopping factor of 6: 1.1-6.4°C above 1990 levels-- hardly "settled science". Projections of precipitation are equivocal even as to the direction of change. Therefore, IPCC Working Group 2 recommends a "risk management" approach to dealing with the combination of well establish and remaining speculative components of global warming that nonetheless pose potentially serious risks to human and natural systems.

  19. Light accelerates plant responses to warming.

    PubMed

    De Frenne, Pieter; Rodríguez-Sánchez, Francisco; De Schrijver, An; Coomes, David A; Hermy, Martin; Vangansbeke, Pieter; Verheyen, Kris

    2015-08-17

    Competition for light has profound effects on plant performance in virtually all terrestrial ecosystems. Nowhere is this more evident than in forests, where trees create environmental heterogeneity that shapes the dynamics of forest-floor communities(1-3). Observational evidence suggests that biotic responses to both anthropogenic global warming and nitrogen pollution may be attenuated by the shading effects of trees and shrubs(4-9). Here we show experimentally that tree shade is slowing down changes in below-canopy communities due to warming. We manipulated levels of photosynthetically active radiation, temperature and nitrogen, alone and in combination, in a temperate forest understorey over a 3-year period, and monitored the composition of the understorey community. Light addition, but not nitrogen enrichment, accelerated directional plant community responses to warming, increasing the dominance of warmth-preferring taxa over cold-tolerant plants (a process described as thermophilization(6,10-12)). Tall, competitive plants took greatest advantage of the combination of elevated temperature and light. Warming of the forest floor did not result in strong community thermophilization unless light was also increased. Our findings suggest that the maintenance of locally closed canopy conditions could reduce, at least temporarily, warming-induced changes in forest floor plant communities.

  20. Global warming: Science or politics. Part 1

    SciTech Connect

    Dorweiler, V.P.

    1998-04-01

    ``The balance of evidence suggests that there has been a discernible influence of human activity on global climate`` is a statement employed as the foundation basis to intervene on behalf of the globe and the future. That statement, as scientific evidence of human-produced greenhouse gases (primarily CO{sub 2}) having a warming effect on global climate is a political statement only. Further, the Kyoto conference to consider intervention in human activities regarding global warming was a political conference. Political and treaty issues were the focus; scientific issues were not much discussed. What change is needed then to scientifically determine global warming and to ascertain whether human activity is involved? A better understanding of the natural climate variations related to solar variation can improve understanding of an anthropogenic greenhouse effect on the climate. The purpose of this article is to pose the scientific question. Part 2 will present an answer.

  1. Vertical structure of recent Arctic warming.

    PubMed

    Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla

    2008-01-01

    Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold season and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of warming that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce warming above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of warming can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.

  2. Communicating the Dangers of Global Warming

    NASA Astrophysics Data System (ADS)

    Hansen, J. E.

    2006-12-01

    So far, in my opinion, we scientists have not done a good job of communicating the imminent threat posed by global warming, yet I believe there is still time for that if we work efficiently now to overcome existing obstacles. Several of those obstacles are illustrated by contrasting the roles of scientists, the media, special interests, politicians and the public in the ozone depletion and global warming crises. Scientists in America are further challenged by a decline in public science education, a perceived gap between science and religion, increasing politicization of public affairs offices in the government, and accumulation of power by a unitary executive. First order communication tasks are illustrated by a need for improved exchange and understanding, among scientists as well as with the public, of fundamental climate facts: (1) additional global warming exceeding 1C will yield large climate effects, (2) paleoclimate changes contain quantitatively specific information about climate sensitivity that is not widely appreciated, (3) carbon cycle facts, such as the substantial portion of carbon dioxide emissions that will remain in the air "forever", for practical purposes, (4) fossil fuel facts such as the dominant role of coal and unconventional fuels in all business-as-usual scenarios for future energy sources. The facts graphically illustrate the need for prompt actions to avoid disastrous climate change, yet they also reveal the feasibility of a course that minimizes global warming and yields other benefits. Perhaps the greatest challenge is posed by an inappropriate casting of the topic as a dichotomy between those who deny that there is a global warming problem and those who either are exceedingly pessimistic about the prospects for minimizing climate change or believe that solutions would be very expensive. Sensible evaluation of the situation, in my opinion, suggests a strategy for dealing with global warming that is not costly and has many subsidiary

  3. Even warm climates get the shivers

    SciTech Connect

    Kerr, R.A.

    1993-07-16

    Researchers in the Greenland Ice-Core Project (GRIP) have found evidence of sharp climate shifts during the last two intergalcials. The Greenland ice sheet evidence shows that Greenland, over and over for decades to thousands of years, cooled drastically from temperatures equal to or higher than today's, often to virtual ice age conditions. The researchers believe that disruptions in the flow of warm water from the southern Atlantic to the North Atlantic, and the return flow of cold water to the south, may be linked to these climatic fluctuations. The present climate appears relatively stable, but that may change if temperatures warm due to increases in atmospheric greenhouse gases.

  4. Global warming: a public health concern.

    PubMed

    Afzal, Brenda M

    2007-05-01

    Over the last 100 years the average temperature on the Earth has risen approximately 1ºFahrenheit (F), increasing at a rate twice as fast as has been noted for any period in the last 1,000 years. The Arctic ice cap is shrinking, glaciers are melting, and the Arctic permafrost is thawing. There is mounting evidence that these global climate changes are already affecting human health. This article provides a brief overview of global warming and climate changes, discusses effects of climate change on health, considers the factors which contribute to climate changes, and reviews individual and collective efforts related to reducing global warming. PMID:21848352

  5. The recent warming trend in North Greenland

    NASA Astrophysics Data System (ADS)

    Orsi, Anais; Kawamura, Kenji; Masson-Delmotte, Valerie; Landais, Amaelle; Severinghaus, Jeff

    2015-04-01

    The arctic is the fastest warming region on Earth, but it is also one where there is little historical data. Although summer warming causes melt, the annual temperature trend is dominated by the winter and fall season, which are much less well documented. In addition, the instrumental record relies principally on coastal weather stations, and there are very few direct temperature observations in the interior dating back more than 30 years, especially in North Greenland, where the current warming trend is the largest. Here, we present a temperature reconstruction from NEEM (51°W, 77°N), in North Greenland, for the last 100 years, which allows us to put the recent trend in the context of the longer term climate. We use a combination of two independent proxies to reconstruct the temperature history at NEEM: borehole temperature and inert gas isotope measurements in the firn. Borehole temperature takes advantage of the low temperature diffusivity of the snow and ice, which allows the temperature history to be preserved in the ice for several centuries. Temperature gradients in the firn (old snow above the ice) influence the gas isotopic composition: thermal fractionation causes heavy isotopes to concentrate on the cold end of the firn column. We measured the isotopes of inert gases (N2, Ar and Kr), which have a constant atmospheric composition through time, and use the thermal fractionation signal as an additional constraint on the temperature history at the site. We find that NEEM has been warming by 0.86±0.22°C/decade over the past 30 years, from -28.55±0.29°C for the 1900-1970 average to -26.77±0.16°C for the 2000-2010 average. The warming rate at NEEM is similar to that of Greenland Summit, and confirms the large warming trends in North Greenland (polar amplification) and high altitude sites (tropospheric rather than surface warming). Water isotopes show that the recent past has not met the level of the 1928 anomaly; but the average of the past 30 years has

  6. Analysis of data from spacecraft (stratospheric warmings)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Investigations involved a search through existing literature and data to obtain case histories for the six or more stratospheric warmings that occurred in April - May 1969, June - July 1969, August 1969, December 1969 - January 1970, December 1970 - January 1971, and January 1973 - February 1973. For each of these warmings the following steps have been taken in preparation for analysis: (1) defining the nature of the problem; (2) literature search of stratwarmings and solar-terrestrial phenomens; and (3) file of data sources, especially stratospheric temperatures (radiances) and geophysical indices.

  7. Warming of water in a glass

    NASA Astrophysics Data System (ADS)

    Paulins, Paulis; Krauze, Armands; Ozolinsh, Maris; Muiznieks, Andris

    2016-03-01

    The article focuses on the process of water warming from 0 °C in a glass. An experiment is performed that analyses the temperature in the top and bottom layers of water during warming. The experimental equipment is very simple and can be easily set up using devices available in schools. The temperature curves obtained from the experiment help us to understand the process of convection in the glass and to determine the temperature at which the density of water is maximum. In addition, computational fluid dynamics—CFD modeling is carried out to facilitate better comprehension of the phenomenon observed in the experiment.

  8. Global warming: a public health concern.

    PubMed

    Afzal, Brenda M

    2007-05-31

    Over the last 100 years the average temperature on the Earth has risen approximately 1ºFahrenheit (F), increasing at a rate twice as fast as has been noted for any period in the last 1,000 years. The Arctic ice cap is shrinking, glaciers are melting, and the Arctic permafrost is thawing. There is mounting evidence that these global climate changes are already affecting human health. This article provides a brief overview of global warming and climate changes, discusses effects of climate change on health, considers the factors which contribute to climate changes, and reviews individual and collective efforts related to reducing global warming.

  9. Ecology: global warming and amphibian losses.

    PubMed

    Alford, Ross A; Bradfield, Kay S; Richards, Stephen J

    2007-05-31

    Is global warming contributing to amphibian declines and extinctions by promoting outbreaks of the chytrid fungus Batrachochytrium dendrobatidis? Analysing patterns from the American tropics, Pounds et al. envisage a process in which a single warm year triggers die-offs in a particular area (for instance, 1987 in the case of Monteverde, Costa Rica). However, we show here that populations of two frog species in the Australian tropics experienced increasing developmental instability, which is evidence of stress, at least two years before they showed chytrid-related declines. Because the working model of Pounds et al. is incomplete, their test of the climate-linked epidemic hypothesis could be inconclusive.

  10. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Mao, J.

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  11. Global warming and sexual plant reproduction.

    PubMed

    Hedhly, Afif; Hormaza, José I; Herrero, María

    2009-01-01

    The sexual reproductive phase in plants might be particularly vulnerable to the effects of global warming. The direct effect of temperature changes on the reproductive process has been documented previously, and recent data from other physiological processes that are affected by rising temperatures seem to reinforce the susceptibility of the reproductive process to a changing climate. But the reproductive phase also provides the plant with an opportunity to adapt to environmental changes. Understanding phenotypic plasticity and gametophyte selection for prevailing temperatures, along with possible epigenetic changes during this process, could provide new insights into plant evolution under a global-warming scenario.

  12. Dynamic characteristics of observed sudden warmings

    NASA Technical Reports Server (NTRS)

    Dartt, D. G.; Venne, D. E.

    1986-01-01

    The planetary wave dynamics of stratospheric sudden warmings in the Northern Hemisphere for a large number of observed events that occurred during winters from 1970 to 1975 and 1978 to 1981 are investigated. The analysis describes wave propagation and zonal flow interaction from the troposphere upwards to near 50 km, and in some years to near 80 km. Three primary topics are covered here: (1) the interaction of zonally propagating and quasi-stationary planetary waves during warming events; (2) planetary wave influence on zonal flow near the stratopause; and (3) planetary wave propagation to near 80 km as seen from Stratospheric and Mesospheric Sounder (SAMS) data.

  13. Is Europa's Subsurface Water Ocean Warm?

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Ekholm, A. G.; Showman, A. P.; Lorenz, R. D.

    2002-01-01

    Europa's subsurface water ocean may be warm: that is, at the temperature of water's maximum density. This provides a natural explanation of chaos melt-through events and leads to a correct estimate of the age of its surface. Additional information is contained in the original extended abstract.

  14. Global warming and extreme storm surges

    NASA Astrophysics Data System (ADS)

    Grinsted, Aslak

    2013-04-01

    I will show empirical evidence for how global warming has changed extreme storm surge statistics for different regions in the world. Are there any detectable changes beyond what we expect from sea level rise. What does this suggest about the future of hurricane surges such as from hurricane Katrina and superstorm Sandy?

  15. Can Global Warming Heat Up Environmental Education?

    ERIC Educational Resources Information Center

    Mazzatenta, Claudio

    2008-01-01

    Bronx Community College (CUNY) launched "Global Warming Campus Awareness and Action Days" in celebration of Earth Day, 2007. The purpose of this program was to raise awareness of environmental issues in the college population, especially students. To let more students have a grasp of what Environmental Education (EE) is all about, the author…

  16. Warm inflationary model in loop quantum cosmology

    SciTech Connect

    Herrera, Ramon

    2010-06-15

    A warm inflationary universe model in loop quantum cosmology is studied. In general we discuss the condition of inflation in this framework. By using a chaotic potential, V({phi}){proportional_to}{phi}{sup 2}, we develop a model where the dissipation coefficient {Gamma}={Gamma}{sub 0}=constant. We use recent astronomical observations for constraining the parameters appearing in our model.

  17. Climate response: Strong warming at high emissions

    NASA Astrophysics Data System (ADS)

    Frölicher, Thomas L.

    2016-09-01

    The ratio of global temperature change to cumulative emissions is relatively constant up to two trillion tonnes of carbon emissions. Now a new modelling study suggests that the concept of a constant ratio is even applicable to higher cumulative carbon emissions, with important implications for future warming.

  18. Global warming in the public sphere.

    PubMed

    Corfee-Morlot, Jan; Maslin, Mark; Burgess, Jacquelin

    2007-11-15

    Although the science of global warming has been in place for several decades if not more, only in the last decade and a half has the issue moved clearly into the public sphere as a public policy issue and a political priority. To understand how and why this has occurred, it is essential to consider the history of the scientific theory of the greenhouse effect, the evidence that supports it and the mechanisms through which science interacts with lay publics and other elite actors, such as politicians, policymakers and business decision makers. This article reviews why and how climate change has moved from the bottom to the top of the international political agenda. It traces the scientific discovery of global warming, political and institutional developments to manage it as well as other socially mediated pathways for understanding and promoting global warming as an issue in the public sphere. The article also places this historical overview of global warming as a public issue into a conceptual framework for understanding relationships between society and nature with emphasis on the co-construction of knowledge.

  19. Desert Amplification in a Warming Climate.

    PubMed

    Zhou, Liming

    2016-01-01

    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950-2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor. PMID:27538725

  20. Temperature Data Shows Warming in 2001

    NASA Technical Reports Server (NTRS)

    2002-01-01

    TThe figure above depicts how much air temperatures near the Earth's surface changed relative to the global mean temperature from 1951 to 1980. NASA researchers used maps of urban areas derived from city lights data to account for the 'heat island' effect of cities. The red and orange colors show that temperatures are warmer in most regions of the world when compared to the 1951 to 1980 'normal' temperatures. Warming around the world has been widespread, but it is not present everywhere. The largest warming is in Northern Canada, Alaska and Siberia, as indicated by the deeper red colors. The lower 48 United States have become warmer recently, but only enough to make the temperatures comparable to what they were in the 1930s. The scale on the bottom of these temperature anomaly images represent degrees in Celsius. The negative numbers represent cooling and the positive numbers depict warming. Overall, the air temperature near the Earth's surface has warmed by 1oF (0.6oC) globally, on average, over the last century. For more information and additional images, read Satellites Shed Light on a Warmer World. Image courtesy Goddard Institute for Space Studies (GISS).

  1. Desert Amplification in a Warming Climate.

    PubMed

    Zhou, Liming

    2016-08-19

    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950-2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor.

  2. National contributions to observed global warming

    NASA Astrophysics Data System (ADS)

    Damon Matthews, H.; Graham, Tanya L.; Keverian, Serge; Lamontagne, Cassandra; Seto, Donny; Smith, Trevor J.

    2014-01-01

    There is considerable interest in identifying national contributions to global warming as a way of allocating historical responsibility for observed climate change. This task is made difficult by uncertainty associated with national estimates of historical emissions, as well as by difficulty in estimating the climate response to emissions of gases with widely varying atmospheric lifetimes. Here, we present a new estimate of national contributions to observed climate warming, including CO2 emissions from fossil fuels and land-use change, as well as methane, nitrous oxide and sulfate aerosol emissions While some countries’ warming contributions are reasonably well defined by fossil fuel CO2 emissions, many countries have dominant contributions from land-use CO2 and non-CO2 greenhouse gas emissions, emphasizing the importance of both deforestation and agriculture as components of a country’s contribution to climate warming. Furthermore, because of their short atmospheric lifetime, recent sulfate aerosol emissions have a large impact on a country’s current climate contribution We show also that there are vast disparities in both total and per-capita climate contributions among countries, and that across most developed countries, per-capita contributions are not currently consistent with attempts to restrict global temperature change to less than 2 °C above pre-industrial temperatures.

  3. Global Warming 'Pause' - Oceans Reshuffle Heat

    NASA Astrophysics Data System (ADS)

    Nieves, V.; Willis, J. K.; Patzert, W. C.

    2015-12-01

    Despite the fact that greenhouse gases are still increasing and all other indicators show warming-related change (+0.0064 °C/year since 1880 or +0.0077 °C/year during 1993-2002), surface temperatures stopped climbing steadily during the past decade at a rate of +0.0010 °C/year from 2003 to 2012. We show that in recent years, the heat was being trapped in the subsurface waters of the western Pacific and eastern Indian oceans between 100 and 300 m. The movement of warm Pacific water below the surface, also related to the Pacific Decadal Oscillation climatic pattern, temporarily affected surface temperatures and accounted for the global cooling trend in surface temperature. With the Pacific Decadal Oscillation possibly changing to a warm phase, it is likely that the oceans will drive a major surge in global surface warming sometime in the next decade or two. Reference: Nieves, V., Willis, J. K., and Patzert, W. C. (2015). Recent hiatus caused by decadal shift in Indo-Pacific heating. Science, aaa4521.

  4. Desert Amplification in a Warming Climate

    PubMed Central

    Zhou, Liming

    2016-01-01

    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950–2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor. PMID:27538725

  5. Desert Amplification in a Warming Climate

    NASA Astrophysics Data System (ADS)

    Zhou, Liming

    2016-08-01

    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950–2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor.

  6. Global warming -- Science and anti-science

    SciTech Connect

    Preining, O. |

    1995-06-01

    The global warming debate has sparked many facts activities in almost all sectors of human endeavors. There are the hard facts, the measurements of the greenhouse gases, the statistics of human activities responsible for emissions, the demographic figures. There are the soft facts, the interpretations of the hard facts requiring additional assumptions. There are the media, the press, television, for whom environmental problems make good stories, these can be used to rise emotions, to make heroes and antiheroes. There are politicians, the global warming debate can be used even in electron campaigns. Global warming is a topic within and beyond science. The judgment (and hence use) of scientific facts is overwhelmingly influenced by the ``Weltbild`` (underlying beliefs how the world operates), and consequently opposing positions of well-known scientists arise. There are the attempts to invent futures of man on Earth: policies, regulations, laws on nation, international, and global levels shall facilitate a change in the basic behavior of all men. The global warming issue has many facets and cannot be successfully discussed without including, e.g., the North-South dialogue, world population, etc.

  7. Global warming and health: a review.

    PubMed

    Amofah, G K

    1996-08-01

    The paper looks at the phenomenon of global warming and its potential health effects and outlines a number of plausible response by the health sector in developing countries to its threat. It suggests that the health sector should facilitate an international effort at addressing this challenge, mainly through advocacy, epidemiological surveillance and awareness creation.

  8. Precipitation Characteristics in Warm Convective Clouds

    NASA Astrophysics Data System (ADS)

    Xue, H.; Ma, Y.; Feingold, G.

    2011-12-01

    The relationship between radar reflectivity factor Z at 9.6 GHz (3 cm) and rain rate R for warm convective clouds is studied. The objectives are to obtain a reasonable Z-R relationship for use in weather radar observation of warm convective precipitation, and to analyze factors that affect the Z-R relationship. Rain rate R is calculated from the drop size distributions in a large eddy simulation (LES); the drop size distributions from LES are also used as inputs into Quickbeam, a software package for simulating atmospheric radiative characteristics, to get radar reflectivity factor Z. It is found that a uniform Z-R relationship is not valid for the cumulus cloud population that develops for several hours. The Z-R relationship depends on the stage of cloud development and the height relative to cloud base. As expected, a range of R values can all lead to the same Z. This is due to the complicated drop size distributions and may cause large uncertainty in precipitation measurement in warm convective clouds using radar data. This study also investigates the Z-R relationship at 94 GHz (3 mm) to evaluate the possibility of measuring precipitation in warm convective clouds using current millimeter wave cloud radars. Results show that a well-defined Z-R relationship at 94 GHz generally exists when the local rain rate is smaller than 1 mm hour-1. This indicates that a millimeter wave cloud radar can be used to measure light precipitation in warm convective clouds. When precipitation is stronger, the attenuation of the signal due to precipitation particles is significant and the estimation of R from the reflectivity factor Z has bigger uncertainty. The domain-averaged rain rate R can be parameterized as a function of domain-averaged liquid water path and cloud drop concentration for the LES clouds. The result for warm convective clouds in this study is consistent with previous findings for stratiform clouds. This may help to better parameterize the warm convective

  9. Impact of warm winters on microbial growth

    NASA Astrophysics Data System (ADS)

    Birgander, Johanna; Rousk, Johannes; Axel Olsson, Pål

    2014-05-01

    Growth of soil bacteria has an asymmetrical response to higher temperature with a gradual increase with increasing temperatures until an optimum after which a steep decline occurs. In laboratory studies it has been shown that by exposing a soil bacterial community to a temperature above the community's optimum temperature for two months, the bacterial community grows warm-adapted, and the optimum temperature of bacterial growth shifts towards higher temperatures. This result suggests a change in the intrinsic temperature dependence of bacterial growth, as temperature influenced the bacterial growth even though all other factors were kept constant. An intrinsic temperature dependence could be explained by either a change in the bacterial community composition, exchanging less tolerant bacteria towards more tolerant ones, or it could be due to adaptation within the bacteria present. No matter what the shift in temperature tolerance is due to, the shift could have ecosystem scale implications, as winters in northern Europe are getting warmer. To address the question of how microbes and plants are affected by warmer winters, a winter-warming experiment was established in a South Swedish grassland. Results suggest a positive response in microbial growth rate in plots where winter soil temperatures were around 6 °C above ambient. Both bacterial and fungal growth (leucine incorporation, and acetate into ergosterol incorporation, respectively) appeared stimulated, and there are two candidate explanations for these results. Either (i) warming directly influence microbial communities by modulating their temperature adaptation, or (ii) warming indirectly affected the microbial communities via temperature induced changes in bacterial growth conditions. The first explanation is in accordance with what has been shown in laboratory conditions (explained above), where the differences in the intrinsic temperature relationships were examined. To test this explanation the

  10. An apparent hiatus in global warming?

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Fasullo, John T.

    2013-12-01

    Global warming first became evident beyond the bounds of natural variability in the 1970s, but increases in global mean surface temperatures have stalled in the 2000s. Increases in atmospheric greenhouse gases, notably carbon dioxide, create an energy imbalance at the top-of-atmosphere (TOA) even as the planet warms to adjust to this imbalance, which is estimated to be 0.5-1 W m-2 over the 2000s. Annual global fluctuations in TOA energy of up to 0.2 W m-2 occur from natural variations in clouds, aerosols, and changes in the Sun. At times of major volcanic eruptions the effects can be much larger. Yet global mean surface temperatures fluctuate much more than these can account for. An energy imbalance is manifested not just as surface atmospheric or ground warming but also as melting sea and land ice, and heating of the oceans. More than 90% of the heat goes into the oceans and, with melting land ice, causes sea level to rise. For the past decade, more than 30% of the heat has apparently penetrated below 700 m depth that is traceable to changes in surface winds mainly over the Pacific in association with a switch to a negative phase of the Pacific Decadal Oscillation (PDO) in 1999. Surface warming was much more in evidence during the 1976-1998 positive phase of the PDO, suggesting that natural decadal variability modulates the rate of change of global surface temperatures while sea-level rise is more relentless. Global warming has not stopped; it is merely manifested in different ways.

  11. Frequency of Deep Convective Clouds and Global Warming

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Teixeira, Joao

    2008-01-01

    This slide presentation reviews the effect of global warming on the formation of Deep Convective Clouds (DCC). It concludes that nature responds to global warming with an increase in strong convective activity. The frequency of DCC increases with global warming at the rate of 6%/decade. The increased frequency of DCC with global warming alone increases precipitation by 1.7%/decade. It compares the state of the art climate models' response to global warming, and concludes that the parametrization of climate models need to be tuned to more closely emulate the way nature responds to global warming.

  12. Southern Hemisphere and deep-sea warming led deglacial atmospheric CO2 rise and tropical warming.

    PubMed

    Stott, Lowell; Timmermann, Axel; Thunell, Robert

    2007-10-19

    Establishing what caused Earth's largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. We determined the chronology of high- and low-latitude climate change at the last glacial termination by radiocarbon dating benthic and planktonic foraminiferal stable isotope and magnesium/calcium records from a marine core collected in the western tropical Pacific. Deep-sea temperatures warmed by approximately 2 degrees C between 19 and 17 thousand years before the present (ky B.P.), leading the rise in atmospheric CO2 and tropical-surface-ocean warming by approximately 1000 years. The cause of this deglacial deep-water warming does not lie within the tropics, nor can its early onset between 19 and 17 ky B.P. be attributed to CO2 forcing. Increasing austral-spring insolation combined with sea-ice albedo feedbacks appear to be the key factors responsible for this warming.

  13. Discrimination of a major stratospheric warming event in February-March 1984 from earlier minor warmings

    NASA Technical Reports Server (NTRS)

    Johnson, K. W.; Quiroz, R. S.; Gelman, M. E.

    1985-01-01

    As part of its responsibility for stratospheric monitoring, the Climate Analysis Center derives time trends of various dynamic parameters from NMC stratospheric analyses. Selected figures from this stratospheric monitoring data base are published in Climate Diagnostics Bulletin in March and October, after each hemispheric winter. During the Northern Hemisphere winter of December 1983-February 1984 several warming events may be seen in the plot of 60 deg. N zonal mean temperatures for 10 mb. Minor warmings may be noted in early December, late December, mid January and early February. A major warming with the 60 deg. N zonal mean temperatures reaching -40C is observed in late February, associated with a circulation reversal. In all of the minor warming episodes, there is a polarward movement of the Aleutian anticyclone; however, at 10 mb the North Pole remains in the cyclonic circulation of the stratospheric vortex which is not displaced far from its usual position. In the case of the later February major warming, the 10 mb circulation pattern over the North Pole is anticyclonic, and the cyclonic circulation has moved to the south and east with a considerable elongation. Cross sections of heat transport and momentum transport are not dramatically different for the minor and major warming episodes.

  14. OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP BUILDINGS, LOOKING SOUTH SOUTHEAST. THE FUNCTION OF THE FLAT AREA AT CENTER RIGHT IS UNKNOWN. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  15. Cognitive Egocentrism Differentiates Warm and Cold People.

    PubMed

    Boyd, Ryan L; Bresin, Konrad; Ode, Scott; Robinson, Michael D

    2013-02-01

    Warmth-coldness is a fundamental dimension of social behavior. Cold individuals are egocentric in their social relations, whereas warm individuals are not. Previous theorizing suggests that cognitive egocentrism underlies social egocentrism. It was hypothesized that higher levels of interpersonal coldness would predict greater cognitive egocentrism. Cognitive egocentrism was assessed in basic terms through tasks wherein priming a lateralized self-state biased subsequent visual perceptions in an assimilation-related manner. Such effects reflect a tendency to assume that the self's incidental state provides meaningful information concerning the external world. Cognitive egocentrism was evident at high, but not low, levels of interpersonal coldness. The findings reveal a basic difference between warm and cold people, encouraging future research linking cognitive egocentrism to variability in relationship functioning.

  16. Global Warming, Drought and a Greening Planet

    NASA Astrophysics Data System (ADS)

    Donohue, R. J.; Roderick, M. L.; McVicar, T.; Farquhar, G. D.; Yang, Y.

    2015-12-01

    A commonly held perception is that global warming will result in a drier planet with a greater occurrence of droughts. Across water-limited environments, droughts result in declines in vegetation productivity and cover. However, observations indicate that productivity and cover have, on average, been increasing across the globe's water-limited regions. This raises the question of what the relationship is between drought and vegetation, and how might vegetation-water dynamics change as global warming progresses. Of particular interest is the role that CO2 fertilisation has in changing landscape-scale vegetation water use. We will present both observation- and model-based analyses of the possible CO2-driven changes in vegetation cover, productivity and water use.

  17. Management of drought risk under global warming

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Han, Lanying; Jia, Jianying; Song, Lingling; Wang, Jinsong

    2016-07-01

    Drought is a serious ecological problem around the world, and its impact on crops and water availability for humans can jeopardize human life. Although drought has always been common, the drought risk has become increasingly prominent because of the climatic warming that has occurred during the past century. However, it still does not comprehensively understand the mechanisms that determine the occurrence of the drought risk it poses to humans, particularly in the context of global climate change. In this paper, we summarize the progress of research on drought and the associated risk, introduce the principle of a drought "transition" from one stage to another, synthesize the characteristics of key factors and their interactions, discuss the potential effect of climatic warming on drought risk, and use this discussion to define the basic requirements for a drought risk management system. We also discuss the main measures that can be used to prevent or mitigate droughts in the context of a risk management strategy.

  18. Environmental colonialism Leadership and global warming

    SciTech Connect

    Not Available

    1990-02-16

    The vast majority of the world's scientific community believes there is global warming and that it is global problem requiring international cooperation. But policy makers in industrialized countries are at a crossroads:Listen to the skeptics, who demand more proof and who fear economic consequences of an anti-greenhouse campaign, or take the more difficult path of commitment to attacking the problem. Meanwhile, poverty and debt keep. The Third world locked out of any active partnership. This issue of ED highlight their results of recently tapping documents and seminar findings on the subject of global warming. This issue also contains the following: (1) ED Refining Netback Data Series for the US Gulf and West Coasts, Rotterdam, and Singapore as of the February 9, 1990; and (2) ED Fuel Price/Tax Series for countries of the Western Hemisphere, February 1990 edition. 6 figs., 5 tabs.

  19. Indian Ocean warming modulates Pacific climate change

    PubMed Central

    Luo, Jing-Jia; Sasaki, Wataru; Masumoto, Yukio

    2012-01-01

    It has been widely believed that the tropical Pacific trade winds weakened in the last century and would further decrease under a warmer climate in the 21st century. Recent high-quality observations, however, suggest that the tropical Pacific winds have actually strengthened in the past two decades. Precise causes of the recent Pacific climate shift are uncertain. Here we explore how the enhanced tropical Indian Ocean warming in recent decades favors stronger trade winds in the western Pacific via the atmosphere and hence is likely to have contributed to the La Niña-like state (with enhanced east–west Walker circulation) through the Pacific ocean–atmosphere interactions. Further analysis, based on 163 climate model simulations with centennial historical and projected external radiative forcing, suggests that the Indian Ocean warming relative to the Pacific’s could play an important role in modulating the Pacific climate changes in the 20th and 21st centuries. PMID:23112174

  20. Giant natural fluctuation models and anthropogenic warming

    NASA Astrophysics Data System (ADS)

    Lovejoy, S.; Rio Amador, L.; Hébert, R.; Lima, I.

    2016-08-01

    Explanations for the industrial epoch warming are polarized around the hypotheses of anthropogenic warming (AW) and giant natural fluctuations (GNFs). While climate sceptics have systematically attacked AW, up until now they have only invoked GNFs. This has now changed with the publication by D. Keenan of a sample of 1000 series from stochastic processes purporting to emulate the global annual temperature since 1880. While Keenan's objective was to criticize the International Panel on Climate Change's trend uncertainty analysis (their assumption that residuals are only weakly correlated), for the first time it is possible to compare a stochastic GNF model with real data. Using Haar fluctuations, probability distributions, and other techniques of time series analysis, we show that his model has unrealistically strong low-frequency variability so that even mild extrapolations imply ice ages every ≈1000 years. Helped by statistics, the GNF model can easily be scientifically rejected.

  1. Cognitive Egocentrism Differentiates Warm and Cold People.

    PubMed

    Boyd, Ryan L; Bresin, Konrad; Ode, Scott; Robinson, Michael D

    2013-02-01

    Warmth-coldness is a fundamental dimension of social behavior. Cold individuals are egocentric in their social relations, whereas warm individuals are not. Previous theorizing suggests that cognitive egocentrism underlies social egocentrism. It was hypothesized that higher levels of interpersonal coldness would predict greater cognitive egocentrism. Cognitive egocentrism was assessed in basic terms through tasks wherein priming a lateralized self-state biased subsequent visual perceptions in an assimilation-related manner. Such effects reflect a tendency to assume that the self's incidental state provides meaningful information concerning the external world. Cognitive egocentrism was evident at high, but not low, levels of interpersonal coldness. The findings reveal a basic difference between warm and cold people, encouraging future research linking cognitive egocentrism to variability in relationship functioning. PMID:23564985

  2. Parameters of human discomfort in warm environments

    SciTech Connect

    Berglund, L.G.; Cunningham, D.J.

    1986-01-01

    The relationship between thermoregulatory responses during exposure to warm and hot environments and the associated subjective perceptions, e.g., comfort, thermal sensation, etc., have been studied by numerous investigators over a considerable span of time, i.e., roughly 50 years. Skin temperature, mean body temperature, sweating, and percent of skin wettedness have been shown to have a role in comfort, thermal sensation, and perception of skin moisture. This paper reviews studies concerned with the physical and physiological parameters relative to these subjective responses and their level of magnitude, with primary emphasis on warm discomfort and skin moisture. The review indicates that, while utilizing different methodologies for quantification of skin moisture under a wide range of ambient conditions and experimental protocols, the relationship between skin wettedness and discomfort or unpleasantness is consistent and experimentally supported.

  3. Indian Ocean warming modulates Pacific climate change.

    PubMed

    Luo, Jing-Jia; Sasaki, Wataru; Masumoto, Yukio

    2012-11-13

    It has been widely believed that the tropical Pacific trade winds weakened in the last century and would further decrease under a warmer climate in the 21st century. Recent high-quality observations, however, suggest that the tropical Pacific winds have actually strengthened in the past two decades. Precise causes of the recent Pacific climate shift are uncertain. Here we explore how the enhanced tropical Indian Ocean warming in recent decades favors stronger trade winds in the western Pacific via the atmosphere and hence is likely to have contributed to the La Niña-like state (with enhanced east-west Walker circulation) through the Pacific ocean-atmosphere interactions. Further analysis, based on 163 climate model simulations with centennial historical and projected external radiative forcing, suggests that the Indian Ocean warming relative to the Pacific's could play an important role in modulating the Pacific climate changes in the 20th and 21st centuries.

  4. Latitudinal distribution of the recent Arctic warming

    SciTech Connect

    Chylek, Petr; Lesins, Glen K; Wang, Muyin

    2010-12-08

    Increasing Arctic temperature, disappearance of Arctic sea ice, melting of the Greenland ice sheet, sea level rise, increasing strength of Atlantic hurricanes are these impending climate catastrophes supported by observations? Are the recent data really unprecedented during the observational records? Our analysis of Arctic temperature records shows that the Arctic and temperatures in the 1930s and 1940s were almost as high as they are today. We argue that the current warming of the Arctic region is affected more by the multi-decadal climate variability than by an increasing concentration of carbon dioxide. Unfortunately, none of the existing coupled Atmosphere-Ocean General Circulation Models used in the IPCC 2007 cIimate change assessment is able to reproduce neither the observed 20th century Arctic cIimate variability nor the latitudinal distribution of the warming.

  5. Isolating the anthropogenic component of Arctic warming

    SciTech Connect

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; Klett, James D.; Humlum, Ole; Wyatt, Marcia; Dubey, Manvendra K.

    2014-05-28

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. We apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variability from the observed temperature. We find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Furthermore, our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.

  6. Isolating the anthropogenic component of Arctic warming

    DOE PAGESBeta

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; Klett, James D.; Humlum, Ole; Wyatt, Marcia; Dubey, Manvendra K.

    2014-05-28

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. We apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variability frommore » the observed temperature. We find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Furthermore, our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.« less

  7. Early Mars: how warm and how wet?

    PubMed

    Squyres, S W; Kasting, J F

    1994-08-01

    Early in its history, Mars underwent fluvial erosion that has been interpreted as evidence for a warmer, wetter climate. However, no atmosphere composed of only CO2 and H2O appears capable of producing mean planetary temperatures even close to 0 degrees C. Rather than by precipitation, aquifer recharge and ground water seepage may have been enabled by hydrothermal convection driven by geothermal heat and heat associated with impacts. Some climatic warming was probably necessary to allow water to flow for long distances across the surface. Modest warming could be provided by even a low-pressure CO2 atmosphere if it was supplemented with small amounts of CH4, NH3, or SO2. Episodic excursions to high obliquities may also have raised temperatures over some portions of the planet's surface. PMID:11539185

  8. Was early Mars warmed by ammonia?

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.; Brown, L. L.; Acord, J. M.; Pollack, J. B.

    1992-01-01

    Runoff channels and valley networks present on ancient, heavily cratered Martian terrain suggests that the climate of Mars was originally warm and wet. One explanation for the formation of these channels is that the surface was warmed by the greenhouse effect of a dense, CO2 atmosphere. However, recent work shows that this theory is not consistent for the early period of the solar system. One way to increase the surface temperature predicted is to assume that other greenhouse gases were present in Mars' atmosphere in addition to CO2 and H2O. This possible gas is ammonia, NH3. If ammonia was present in sufficient quantities, it could have raised the surface temperature to 273 K. An adequate source would have been volcanic outgassing if the NH3 produced was shielded from photolysis by an ultraviolet light absorber.

  9. [Global warming and spread of infectious diseases].

    PubMed

    Ebert, B; Fleischer, B

    2005-01-01

    At the end of the twentieth century, tropical infectious diseases increased despite earlier successes of eradication campaigns. As a global warming of 1.4-5.8 degrees C is anticipated to occur by 2100, mainly the vector-borne tropical diseases that are particularly sensitive to climate are expected to spread. Although biological reasons seemingly support this hypothesis, ecological and socioeconomic factors have in the past proven to be stronger driving forces for the spread of infectious disease than climate.

  10. Robust warming of the global upper ocean.

    PubMed

    Lyman, John M; Good, Simon A; Gouretski, Viktor V; Ishii, Masayoshi; Johnson, Gregory C; Palmer, Matthew D; Smith, Doug M; Willis, Josh K

    2010-05-20

    A large ( approximately 10(23) J) multi-decadal globally averaged warming signal in the upper 300 m of the world's oceans was reported roughly a decade ago and is attributed to warming associated with anthropogenic greenhouse gases. The majority of the Earth's total energy uptake during recent decades has occurred in the upper ocean, but the underlying uncertainties in ocean warming are unclear, limiting our ability to assess closure of sea-level budgets, the global radiation imbalance and climate models. For example, several teams have recently produced different multi-year estimates of the annually averaged global integral of upper-ocean heat content anomalies (hereafter OHCA curves) or, equivalently, the thermosteric sea-level rise. Patterns of interannual variability, in particular, differ among methods. Here we examine several sources of uncertainty that contribute to differences among OHCA curves from 1993 to 2008, focusing on the difficulties of correcting biases in expendable bathythermograph (XBT) data. XBT data constitute the majority of the in situ measurements of upper-ocean heat content from 1967 to 2002, and we find that the uncertainty due to choice of XBT bias correction dominates among-method variability in OHCA curves during our 1993-2008 study period. Accounting for multiple sources of uncertainty, a composite of several OHCA curves using different XBT bias corrections still yields a statistically significant linear warming trend for 1993-2008 of 0.64 W m(-2) (calculated for the Earth's entire surface area), with a 90-per-cent confidence interval of 0.53-0.75 W m(-2).

  11. Global warming and the hydrologic cycle

    NASA Astrophysics Data System (ADS)

    Loaiciga, Hugo A.; Valdes, Juan B.; Vogel, Richard; Garvey, Jeff; Schwarz, Harry

    1996-01-01

    Starting with a review of the basic processes that govern greenhouse warming, we have demonstrated that the hydrologic cycle plays a key role in the heat balance of the Earth's surface—atmosphere system. Through the water and other climatic feedbacks, the hydrologic cycle is shown to be a key factor in the climate's evolution as greenhouse gases continue to build up in the atmosphere. This paper examines the current predictive capability of general circulation models linked with macroscale and landscape-scale hydrologic models that simulate regional and local hydrologic regimes under global warming scenarios. Issues concerning hydrologic model calibration and validation in the context of climate change are addressed herein. It is shown that the natural uncertainty in hydrologic regimes in the present climate introduces a signal-to-noise interpretation problem for discerning greenhouse-induced variations in regional hydrologic regimes. Simulations of river basins by means of macroscale hydrologic models nested within general circulation models have been implemented in a few selected cases. From the perspective of water resources management, such simulations, carried out in detail under greenhouse-warming scenarios in midlatitudinal basins of the United States, predict shorter winter seasons, larger winter floods, drier and more frequent summer weather, and overall enhanced and protracted hydrologic variability. All these predictions point to potentially worsening conditions for flood control, water storage, and water supply in areas of semiarid midlatitudinal climate currently dependent of spring snowmelt. Little information of this type is currently available for other areas of the world. Practice of sound water resources engineering principles ought to be adequate to cope with additional hydrologic uncertainty that might arise from global warming.

  12. An Implicit Psychology of Warm and Cold Interpersonal Relations.

    ERIC Educational Resources Information Center

    Walker, Charles J.; Sarteschi, Randy

    Currently it is recognized that psychology of people may involve both an implicit theory of interpersonal warmness and the personality trait of warmness. Just as the trait of dominance depends on the relative strengths of interactants, so may perceivers expect the trait of warmness to derive its meaning from an interpersonal context. Elements of…

  13. Urbanization enhances surface warming in Eastern China

    NASA Astrophysics Data System (ADS)

    Wang, Dagang

    2016-04-01

    This study aims at observing urban effects on surface warming in eastern China, where many cities have undergone a rapid development of urbanization in the last few decades. Daily mean, maximum and minimum surface air temperature records from 1971-2010 in 277 meteorological stations are used to investigate the effects of urbanization on temperature change. Due to the expansion of cities, the temperature records in some of the stations which were not close to cities in the past are gradually influenced by urbanization. In order to detect the effects of urbanization on surface warming effectively, the stations are classified into 'urban' and 'rural' types dynamically based on the land use data in four periods, 1980, 1990, 2000 and 2010 in this study. By comparing the temperature trend differences between all of the urban and rural stations in eastern China, the results show that annual averaged daily minimum temperature are suffered the strongest effects from urbanization with an increased rate of 0.870°C decade-1 in urban stations, and the contribution of urban effects to its total surface warming is estimated to be 52.8% during 1971-2010.

  14. Effects of Global Warming on Vibrio Ecology.

    PubMed

    Vezzulli, Luigi; Pezzati, Elisabetta; Brettar, Ingrid; Höfle, Manfred; Pruzzo, Carla

    2015-06-01

    Vibrio-related infections are increasing worldwide both in humans and aquatic animals. Rise in global sea surface temperature (SST), which is approximately 1 °C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases. In this chapter, major known effects of increasing SST on the biology and ecology of vibrios are described. They include the effects on bacterial growth rate, both in the field and in laboratory, culturability, expression of pathogenicity traits, and interactions with aquatic organisms and abiotic surfaces. Special emphasis is given to the effect of ocean warming on Vibrio interactions with zooplankters, which represent one of the most important aquatic reservoirs for these bacteria. The reported findings highlight the biocomplexity of the interactions between vibrios and their natural environment in a climate change scenario, posing the need for interdisciplinary studies to properly understand the connection between ocean warming and persistence and spread of vibrios in sea waters and the epidemiology of the diseases they cause. PMID:26185070

  15. Scientists' views about attribution of global warming.

    PubMed

    Verheggen, Bart; Strengers, Bart; Cook, John; van Dorland, Rob; Vringer, Kees; Peters, Jeroen; Visser, Hans; Meyer, Leo

    2014-08-19

    Results are presented from a survey held among 1868 scientists studying various aspects of climate change, including physical climate, climate impacts, and mitigation. The survey was unique in its size, broadness and level of detail. Consistent with other research, we found that, as the level of expertise in climate science grew, so too did the level of agreement on anthropogenic causation. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), explicitly agreed with anthropogenic greenhouse gases (GHGs) being the dominant driver of recent global warming. The respondents' quantitative estimate of the GHG contribution appeared to strongly depend on their judgment or knowledge of the cooling effect of aerosols. The phrasing of the IPCC attribution statement in its fourth assessment report (AR4)-providing a lower limit for the isolated GHG contribution-may have led to an underestimation of the GHG influence on recent warming. The phrasing was improved in AR5. We also report on the respondents' views on other factors contributing to global warming; of these Land Use and Land Cover Change (LULCC) was considered the most important. Respondents who characterized human influence on climate as insignificant, reported having had the most frequent media coverage regarding their views on climate change.

  16. Global Warming: Evidence from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

    2001-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown on-board sequential, sun-synchronous, polar orbiting NOAA operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study we have minimized systematic errors in the time series introduced by the satellite orbital drift in an objective manner. This is done with the help the onboard warm black body temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically weighted global mean temperature of the atmosphere, with a peak weight near the mid-troposphere, warmed at the rate of 0.13 K per decade (with an uncertainty of 0.05 K per decade) during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite deuced result.

  17. Effects of Global Warming on Vibrio Ecology.

    PubMed

    Vezzulli, Luigi; Pezzati, Elisabetta; Brettar, Ingrid; Höfle, Manfred; Pruzzo, Carla

    2015-06-01

    Vibrio-related infections are increasing worldwide both in humans and aquatic animals. Rise in global sea surface temperature (SST), which is approximately 1 °C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases. In this chapter, major known effects of increasing SST on the biology and ecology of vibrios are described. They include the effects on bacterial growth rate, both in the field and in laboratory, culturability, expression of pathogenicity traits, and interactions with aquatic organisms and abiotic surfaces. Special emphasis is given to the effect of ocean warming on Vibrio interactions with zooplankters, which represent one of the most important aquatic reservoirs for these bacteria. The reported findings highlight the biocomplexity of the interactions between vibrios and their natural environment in a climate change scenario, posing the need for interdisciplinary studies to properly understand the connection between ocean warming and persistence and spread of vibrios in sea waters and the epidemiology of the diseases they cause.

  18. Global Warming: Evidence from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R.; Yoo, J.-M.; Dalu, G.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown onboard sequential, sun-synchronous, polar-orbiting NOAA (National Oceanic and Atmospheric Administration) operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study, we have minimized systematic errors in the time series introduced by satellite orbital drift in an objective manner. This is done with the help of the onboard warm-blackbody temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically-weighted global-mean temperature of the atmosphere, with a peak weight near the mid troposphere, warmed at the rate of 0.13 +/- 0.05 K/decade during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite-deduced result.

  19. Toward international law on global warming

    SciTech Connect

    Shultz, E.B. Jr.; Johns, C.; Pauken, M.T. )

    1991-01-01

    Legal precedent in the history of international environmental law is considered. Then, the legal principles, rights and obligations related to transboundary environmental interference are drawn from the precedent. From this legal and historical background, and a brief overview of the principal technical aspects of the emerging global warming problem, the authors suggest a number of possible international protocols. These include outlines of multilateral treaties on energy efficiency, reduction in utilization of coal, increased adoption efficiency, reduction in utilization of coal, increased adoption of renewable and solar energy, and stimulation of several types of forestation, with creation of practical regimes and remedies. Each protocol has its own environmental social and economic merits and urgency, apart from the prevention of global warming. In each suggested protocol, the political obstacles are analyzed. Suggestions are presented for reduction of levels of disagreement standing in the way of obtaining viable treaties likely to be upheld in practice by the signatories. An agenda for study and action is presented, on the assumption that prudence dictates that international environmental law must be expanded as soon as feasible to regulate global warming.

  20. Seaweed communities in retreat from ocean warming.

    PubMed

    Wernberg, Thomas; Russell, Bayden D; Thomsen, Mads S; Gurgel, C Frederico D; Bradshaw, Corey J A; Poloczanska, Elvira S; Connell, Sean D

    2011-11-01

    In recent decades, global climate change [1] has caused profound biological changes across the planet [2-6]. However, there is a great disparity in the strength of evidence among different ecosystems and between hemispheres: changes on land have been well documented through long-term studies, but similar direct evidence for impacts of warming is virtually absent from the oceans [3, 7], where only a few studies on individual species of intertidal invertebrates, plankton, and commercially important fish in the North Atlantic and North Pacific exist. This disparity of evidence is precarious for biological conservation because of the critical role of the marine realm in regulating the Earth's environmental and ecological functions, and the associated socioeconomic well-being of humans [8]. We interrogated a database of >20,000 herbarium records of macroalgae collected in Australia since the 1940s and documented changes in communities and geographical distribution limits in both the Indian and Pacific Oceans, consistent with rapid warming over the past five decades [9, 10]. We show that continued warming might drive potentially hundreds of species toward and beyond the edge of the Australian continent where sustained retreat is impossible. The potential for global extinctions is profound considering the many endemic seaweeds and seaweed-dependent marine organisms in temperate Australia.

  1. Global warming and allergy in Asia Minor.

    PubMed

    Bajin, Munir Demir; Cingi, Cemal; Oghan, Fatih; Gurbuz, Melek Kezban

    2013-01-01

    The earth is warming, and it is warming quickly. Epidemiological studies have demonstrated that global warming is correlated with the frequency of pollen-induced respiratory allergy and allergic diseases. There is a body of evidence suggesting that the prevalence of allergic diseases induced by pollens is increasing in developed countries, a trend that is also evident in the Mediterranean area. Because of its mild winters and sunny days with dry summers, the Mediterranean area is different from the areas of central and northern Europe. Classical examples of allergenic pollen-producing plants of the Mediterranean climate include Parietaria, Olea and Cupressaceae. Asia Minor is a Mediterranean region that connects Asia and Europe, and it includes considerable coastal areas. Gramineae pollens are the major cause of seasonal allergic rhinitis in Asia Minor, affecting 1.3-6.4 % of the population, in accordance with other European regions. This article emphasizes the importance of global climate change and anticipated increases in the prevalence and severity of allergic disease in Asia Minor, mediated through worsening air pollution and altered local and regional pollen production, from an otolaryngologic perspective.

  2. Attribution of polar warming to human influence

    NASA Astrophysics Data System (ADS)

    Gillett, Nathan P.; Stone, Dáithí A.; Stott, Peter A.; Nozawa, Toru; Karpechko, Alexey Yu.; Hegerl, Gabriele C.; Wehner, Michael F.; Jones, Philip D.

    2008-11-01

    The polar regions have long been expected to warm strongly as a result of anthropogenic climate change, because of the positive feedbacks associated with melting ice and snow. Several studies have noted a rise in Arctic temperatures over recent decades, but have not formally attributed the changes to human influence, owing to sparse observations and large natural variability. Both warming and cooling trends have been observed in Antarctica, which the Intergovernmental Panel on Climate Change Fourth Assessment Report concludes is the only continent where anthropogenic temperature changes have not been detected so far, possibly as a result of insufficient observational coverage. Here we use an up-to-date gridded data set of land surface temperatures and simulations from four coupled climate models to assess the causes of the observed polar temperature changes. We find that the observed changes in Arctic and Antarctic temperatures are not consistent with internal climate variability or natural climate drivers alone, and are directly attributable to human influence. Our results demonstrate that human activities have already caused significant warming in both polar regions, with likely impacts on polar biology, indigenous communities, ice-sheet mass balance and global sea level.

  3. Multishock Compression Properties of Warm Dense Argon

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Chen, Qifeng; Yunjun, Gu; Li, Zhiguo; Shen, Zhijun

    2015-10-01

    Warm dense argon was generated by a shock reverberation technique. The diagnostics of warm dense argon were performed by a multichannel optical pyrometer and a velocity interferometer system. The equations of state in the pressure-density range of 20-150 GPa and 1.9-5.3 g/cm3 from the first- to fourth-shock compression were presented. The single-shock temperatures in the range of 17.2-23.4 kK were obtained from the spectral radiance. Experimental results indicates that multiple shock-compression ratio (ηi = ρi/ρ0) is greatly enhanced from 3.3 to 8.8, where ρ0 is the initial density of argon and ρi (i = 1, 2, 3, 4) is the compressed density from first to fourth shock, respectively. For the relative compression ratio (ηi’ = ρi/ρi-1), an interesting finding is that a turning point occurs at the second shocked states under the conditions of different experiments, and ηi’ increases with pressure in lower density regime and reversely decreases with pressure in higher density regime. The evolution of the compression ratio is controlled by the excitation of internal degrees of freedom, which increase the compression, and by the interaction effects between particles that reduce it. A temperature-density plot shows that current multishock compression states of argon have distributed into warm dense regime.

  4. Multishock Compression Properties of Warm Dense Argon.

    PubMed

    Zheng, Jun; Chen, Qifeng; Yunjun, Gu; Li, Zhiguo; Shen, Zhijun

    2015-01-01

    Warm dense argon was generated by a shock reverberation technique. The diagnostics of warm dense argon were performed by a multichannel optical pyrometer and a velocity interferometer system. The equations of state in the pressure-density range of 20-150 GPa and 1.9-5.3 g/cm(3) from the first- to fourth-shock compression were presented. The single-shock temperatures in the range of 17.2-23.4 kK were obtained from the spectral radiance. Experimental results indicates that multiple shock-compression ratio (ηi = ρi/ρ0) is greatly enhanced from 3.3 to 8.8, where ρ0 is the initial density of argon and ρi (i = 1, 2, 3, 4) is the compressed density from first to fourth shock, respectively. For the relative compression ratio (ηi' = ρi/ρi-1), an interesting finding is that a turning point occurs at the second shocked states under the conditions of different experiments, and ηi' increases with pressure in lower density regime and reversely decreases with pressure in higher density regime. The evolution of the compression ratio is controlled by the excitation of internal degrees of freedom, which increase the compression, and by the interaction effects between particles that reduce it. A temperature-density plot shows that current multishock compression states of argon have distributed into warm dense regime. PMID:26515505

  5. Wind changes above warm Agulhas Current eddies

    NASA Astrophysics Data System (ADS)

    Rouault, M.; Verley, P.; Backeberg, B.

    2016-04-01

    Sea surface temperature (SST) estimated from the Advanced Microwave Scanning Radiometer E onboard the Aqua satellite and altimetry-derived sea level anomalies are used south of the Agulhas Current to identify warm-core mesoscale eddies presenting a distinct SST perturbation greater than to 1 °C to the surrounding ocean. The analysis of twice daily instantaneous charts of equivalent stability-neutral wind speed estimates from the SeaWinds scatterometer onboard the QuikScat satellite collocated with SST for six identified eddies shows stronger wind speed above the warm eddies than the surrounding water in all wind directions, if averaged over the lifespan of the eddies, as was found in previous studies. However, only half of the cases showed higher wind speeds above the eddies at the instantaneous scale; 20 % of cases had incomplete data due to partial global coverage by the scatterometer for one path. For cases where the wind is stronger above warm eddies, there is no relationship between the increase in surface wind speed and the SST perturbation, but we do find a linear relationship between the decrease in wind speed from the centre to the border of the eddy downstream and the SST perturbation. SST perturbations range from 1 to 6 °C for a mean eddy SST of 15.9 °C and mean SST perturbation of 2.65 °C. The diameter of the eddies range from 100 to 250 km. Mean background wind speed is about 12 m s-1 (mostly southwesterly to northwesterly) and ranging mainly from 4 to 16 m s-1. The mean wind increase is about 15 %, which corresponds to 1.8 m s-1. A wind speed increase of 4 to 7 m s-1 above warm eddies is not uncommon. Cases where the wind did not increase above the eddies or did not decrease downstream had higher wind speeds and occurred during a cold front associated with intense cyclonic low-pressure systems, suggesting certain synoptic conditions need to be met to allow for the development of wind speed anomalies over warm-core ocean eddies. In many cases

  6. Arctic Warming Signals from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2005-01-01

    Global warming signals are expected to be amplified in the Arctic primarily because of ice-albedo feedback associated with the high reflectivity of ice and snow that blankets much of the region. The Arctic had been a poorly explored territory basically because of its general inaccessibility on account of extremely harsh weather conditions and the dominant presence of thick perennial ice in the region. The advent of satellite remote sensing systems since the 1960s, however, enabled the acquisition of synoptic data that depict in good spatial detail the temporal changes of many Arctic surface parameters. Among the surface parameters that have been studied using space based systems are surface temperature, sea ice concentration, snow cover, surface albedo and phytoplankton concentration. Associated atmospheric parameters, such as cloud cover, temperature profile, ozone concentration, and aerosol have also been derived. Recent observational and phenomenological studies have indeed revealed progressively changing conditions in the Arctic during the last few decades (e g , Walsh et al. 1996; Serreze et al 2000; Comiso and Parkinson 2004). The changes included declines in the extent and area of surfaces covered by sea ice and snow, increases in melt area over the Greenland ice sheets, thawing of the permafrost, warming in the troposphere, and retreat of the glaciers. These observations are consistent with the observed global warming that has been associated with the increasing concentration of greenhouse gases in the atmosphere (Karl and Trenberth 2003) and confirmed by modeling studies (Holland and Bitz, 2003). The Arctic system, however, is still not well understood complicated by a largely fluctuating wind circulation and atmospheric conditions (Proshutinsky and Johnson 1997) and controlled by what is now known as the Arctic Oscillation (AO) which provides a measure of the strength of atmospheric activities in the region (Thompson and Wallace 1998). Meanwhile, the

  7. Can cirrus clouds warm early Mars?

    NASA Astrophysics Data System (ADS)

    Ramirez, R. M.

    2015-12-01

    The presence of the ancient valley networks on Mars indicates a climate 3.8 Ga that was warm enough to allow substantial liquid water to flow on the martian surface for extended periods of time. However, the origin of these enigmatic features is hotly debated and discussion of their formation has been focused on how warm such a climate may have been and for how long. Recent warm and wet solutions using single-column radiative convective models involve supplementing CO2-H2O atmospheres with other greenhouse gases, such as H2 (i.e. Ramirez et al., 2014; Batalha et al., 2015). An interesting recent proposal, using the CAM 3-D General Circulation model, argues that global cirrus cloud decks in CO2-H2O atmospheres with at least 0.25 bar of CO2 , consisting of 10-micron (and larger) sized particles, could have generated the above-freezing temperatures required to explain the early martian surface geology (Urata and Toon, 2013). Here, we use our single-column radiative convective climate model to check these 3-D results and analyze the likelihood that such warm atmospheres, with mean surface pressures of up to 3 bar, could have supported cirrus cloud decks at full and fractional cloud cover for sufficiently long durations to form the ancient valleys. Our results indicate that cirrus cloud decks could have provided the mean surface temperatures required, but only if cloud cover approaches 100%, in agreement with Urata and Toon (2013). However, even should cirrus cloud coverage approach 100%, we show that such atmospheres are likely to have been too short-lived to produce the volumes of water required to carve the ancient valleys. At more realistic early Mars cloud fractions (~50%, Forget et al., 2013), cirrus clouds do not provide the required warming. Batalha, N., Domagal-Goldman, S. D., Ramirez, R.M., & Kasting, J. F., 2015. Icarus, 258, 337-349. Forget, F., Wordsworth, R., Millour, E., Madeleine, J. B., Kerber, L., Leconte, J., ... & Haberle, R. M., 2013. Icarus, 222

  8. Warm-up and performance in competitive swimming.

    PubMed

    Neiva, Henrique P; Marques, Mário C; Barbosa, Tiago M; Izquierdo, Mikel; Marinho, Daniel A

    2014-03-01

    Warm-up before physical activity is commonly accepted to be fundamental, and any priming practices are usually thought to optimize performance. However, specifically in swimming, studies on the effects of warm-up are scarce, which may be due to the swimming pool environment, which has a high temperature and humidity, and to the complexity of warm-up procedures. The purpose of this study is to review and summarize the different studies on how warming up affects swimming performance, and to develop recommendations for improving the efficiency of warm-up before competition. Most of the main proposed effects of warm-up, such as elevated core and muscular temperatures, increased blood flow and oxygen delivery to muscle cells and higher efficiency of muscle contractions, support the hypothesis that warm-up enhances performance. However, while many researchers have reported improvements in performance after warm-up, others have found no benefits to warm-up. This lack of consensus emphasizes the need to evaluate the real effects of warm-up and optimize its design. Little is known about the effectiveness of warm-up in competitive swimming, and the variety of warm-up methods and swimming events studied makes it difficult to compare the published conclusions about the role of warm-up in swimming. Recent findings have shown that warm-up has a positive effect on the swimmer's performance, especially for distances greater than 200 m. We recommend that swimmers warm-up for a relatively moderate distance (between 1,000 and 1,500 m) with a proper intensity (a brief approach to race pace velocity) and recovery time sufficient to prevent the early onset of fatigue and to allow the restoration of energy reserves (8-20 min). PMID:24178508

  9. Global warming, bad weather, insurance losses and the global economy

    SciTech Connect

    Low, N.C.; Shen, S.

    1996-09-01

    Global warming causes extremely bad weather in the near term. The impact on the insurance industry is described. Why global warming in the near term causes very bad weather is explained. The continuing trend of very bad weather and the future impact on the insurance industry is explored. How very bad weather can affect the global financial market is explained. Taking a historical view of the development of the modern economy, the authors describe in the near term the impact of global warming on the global economy. The long term impact of global warming on the global economy and the human race is explored. Opportunities presented by global warming are described.

  10. Global warming 2007. An update to global warming: the balance of evidence and its policy implications.

    PubMed

    Keller, Charles F

    2007-03-09

    In the four years since my original review (Keller[25]; hereafter referred to as CFK03), research has clarified and strengthened our understanding of how humans are warming the planet. So many of the details highlighted in the IPCC's Third Assessment Report[21] and in CFK03 have been resolved that I expect many to be a bit overwhelmed, and I hope that, by treating just the most significant aspects of the research, this update may provide a road map through the expected maze of new information. In particular, while most of CFK03 remains current, there are important items that have changed: Most notable is the resolution of the conundrum that mid-tropospheric warming did not seem to match surface warming. Both satellite and radiosonde (balloon-borne sensors) data reduction showed little warming in the middle troposphere (4-8 km altitude). In the CFK03 I discussed potential solutions to this problem, but at that time there was no clear resolution. This problem has now been solved, and the middle troposphere is seen to be warming apace with the surface. There have also been advances in determinations of temperatures over the past 1,000 years showing a cooler Little Ice Age (LIA) but essentially the same warming during medieval times (not as large as recent warming). The recent uproar over the so-called "hockey stick" temperature determination is much overblown since at least seven other groups have made relatively independent determinations of northern hemisphere temperatures over the same time period and derived essentially the same results. They differ on how cold the LIA was but essentially agree with the Mann's hockey stick result that the Medieval Warm Period was not as warm as the last 25 years. The question of the sun's influence on climate continues to generate controversy. It appears there is a growing consensus that, while the sun was a major factor in earlier temperature variations, it is incapable of having caused observed warming in the past quarter

  11. Deep time evidence for climate sensitivity increase with warming

    NASA Astrophysics Data System (ADS)

    Shaffer, Gary; Huber, Matthew; Rondanelli, Roberto; Pepke Pedersen, Jens Olaf

    2016-06-01

    Future global warming from anthropogenic greenhouse gas emissions will depend on climate feedbacks, the effect of which is expressed by climate sensitivity, the warming for a doubling of atmospheric CO2 content. It is not clear how feedbacks, sensitivity, and temperature will evolve in our warming world, but past warming events may provide insight. Here we employ paleoreconstructions and new climate-carbon model simulations in a novel framework to explore a wide scenario range for the Paleocene-Eocene Thermal Maximum (PETM) carbon release and global warming event 55.8 Ma ago, a possible future warming analogue. We obtain constrained estimates of CO2 and climate sensitivity before and during the PETM and of the PETM carbon input amount and nature. Sensitivity increased from 3.3-5.6 to 3.7-6.5 K (Kelvin) into the PETM. When taken together with Last Glacial Maximum and modern estimates, this result indicates climate sensitivity increase with global warming.

  12. Simulation of future global warming scenarios in rice paddies with an open-field warming facility

    PubMed Central

    2011-01-01

    To simulate expected future global warming, hexagonal arrays of infrared heaters have previously been used to warm open-field canopies of upland crops such as wheat. Through the use of concrete-anchored posts, improved software, overhead wires, extensive grounding, and monitoring with a thermal camera, the technology was safely and reliably extended to paddy rice fields. The system maintained canopy temperature increases within 0.5°C of daytime and nighttime set-point differences of 1.3 and 2.7°C 67% of the time. PMID:22145582

  13. Punishments and Prizes for Explaining Global Warming

    NASA Astrophysics Data System (ADS)

    Somerville, R. C.

    2006-12-01

    Some few gifted scientists, the late Carl Sagan being an iconic example, are superbly skilled at communicating science clearly and compellingly to non-scientists. Most scientists, however, have serious shortcomings as communicators. The common failings include being verbose, addicted to jargon, caveat- obsessed and focused on details. In addition, it is far easier for a scientist to scoff at the scientific illiteracy of modern society than to work at understanding the viewpoints and concerns of journalists, policymakers and the public. Obstacles await even those scientists with the desire and the talent to communicate science well. Peer pressure and career disincentives can act as powerful deterrents, discouraging especially younger scientists from spending time on non-traditional activities. Scientists often lack mentors and role models to help them develop skills in science communication. Journalists also face real difficulties in getting science stories approved by editors and other gatekeepers. Climate change science brings its own problems in communication. The science itself is unusually wide- ranging and complex. The contentious policies and politics of dealing with global warming are difficult to disentangle from the science. Misinformation and disinformation about climate change are widespread. Intimidation and censorship of scientists by some employers is a serious problem. Polls show that global warming ranks low on the public's list of important issues. Despite all the obstacles, communicating climate change science well is critically important today. It is an art that can be learned and that brings its own rewards and satisfactions. Academic institutions and research funding agencies increasingly value outreach by scientists, and they provide resources to facilitate it. Society needs scientists who can clearly and authoritatively explain the science of global warming and its implications, while remaining objective and policy-neutral. This need will

  14. Multishock Compression Properties of Warm Dense Argon

    PubMed Central

    Zheng, Jun; Chen, Qifeng; Yunjun, Gu; Li, Zhiguo; Shen, Zhijun

    2015-01-01

    Warm dense argon was generated by a shock reverberation technique. The diagnostics of warm dense argon were performed by a multichannel optical pyrometer and a velocity interferometer system. The equations of state in the pressure-density range of 20–150 GPa and 1.9–5.3 g/cm3 from the first- to fourth-shock compression were presented. The single-shock temperatures in the range of 17.2–23.4 kK were obtained from the spectral radiance. Experimental results indicates that multiple shock-compression ratio (ηi = ρi/ρ0) is greatly enhanced from 3.3 to 8.8, where ρ0 is the initial density of argon and ρi (i = 1, 2, 3, 4) is the compressed density from first to fourth shock, respectively. For the relative compression ratio (ηi’ = ρi/ρi-1), an interesting finding is that a turning point occurs at the second shocked states under the conditions of different experiments, and ηi’ increases with pressure in lower density regime and reversely decreases with pressure in higher density regime. The evolution of the compression ratio is controlled by the excitation of internal degrees of freedom, which increase the compression, and by the interaction effects between particles that reduce it. A temperature-density plot shows that current multishock compression states of argon have distributed into warm dense regime. PMID:26515505

  15. Global warming: Science or politics? Part 2

    SciTech Connect

    Dorweiler, V.P.

    1998-05-01

    Supplementing the conclusion that ``there has been a discernible influence of human activity on global climate`` is a set of dire consequences to the globe and human population. One consequence is the spread of tropical diseases. It has not been concluded whether the spread of disease is due to global conditions or to opening of tropical forests to commerce, allowing spread by travelers. Whether these forecasts abet the claimed relation of human activity to global warming, they are not a new phenomenon. In the space of several decades, dire consequences have been forecast in three sectors: natural resource consumption, energy resources and environmental fate. These three areas are reviewed.

  16. Warm-Polytropic Inflationary Universe Model

    NASA Astrophysics Data System (ADS)

    Setare, M. R.; Houndjo, M. J. S.; Kamali, V.

    2013-07-01

    In this paper, we study warm inflationary universe models in the context of a polytropic gas. We derive the characteristics of this model in slow-roll approximation and develop our model in two cases: (1) for a constant dissipative parameter Γ; (2) Γ as a function of scalar field ϕ. In these cases, we will obtain exact solution for the scalar field and Hubble parameter. We will also obtain explicit expressions for the tensor-scalar ratio R, scalar spectrum index ns and its running αs in slow-roll approximation.

  17. Does coral bleaching mean global warming

    SciTech Connect

    Miller, J.A.

    1991-02-01

    This article discusses the implications of global warming on the marine ecosystems. In recent hearings of the US Senate Committee on Commerce, Science and Transportation, plans were made to introduce legislation for control of greenhouse-gas emissions, conservation of biological diversity, forest conservation, world population planning, sustainable economic development , increased fuel efficiency, and increased research into Earth-system processes. Research is required to ascertain the meaning of coral bleaching, which is the mass expulsion of symbiotic algae, called zooxanthellae, which gives the coral its color. Many scientists think that the death of the algae is an early indicator for massive destruction of the marine ecosystem.

  18. Large-scale dynamics and global warming

    SciTech Connect

    Held, I.M. )

    1993-02-01

    Predictions of future climate change raise a variety of issues in large-scale atmospheric and oceanic dynamics. Several of these are reviewed in this essay, including the sensitivity of the circulation of the Atlantic Ocean to increasing freshwater input at high latitudes; the possibility of greenhouse cooling in the southern oceans; the sensitivity of monsoonal circulations to differential warming of the two hemispheres; the response of midlatitude storms to changing temperature gradients and increasing water vapor in the atmosphere; and the possible importance of positive feedback between the mean winds and eddy-induced heating in the polar stratosphere.

  19. Warm Dust in the RCRA Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Leene, A.; Beichman, C. A.

    The authors report on IRAS observations of a portion of the R CrA molecular cloud. The observations show IR emission coinciding with an area of low optical extinction. The 60 - 100 μm color temperature of this dust is 21K. The 12 - 25 μm color temperature is however 400K. The emission of this warm dust extends over an area of 0.3 square degrees. This high temperature can not be explained by normal equilibrium processes. The observations imply the existence of very small grains, which are heated by single photon absorptions.

  20. Warming Early Mars With CH4

    NASA Astrophysics Data System (ADS)

    Justh, H. L.; Kasting, J. F.

    2002-12-01

    The nature of the ancient climate of Mars remains one of the fundamental unresolved problems in martian research. While the present environment is hostile to life, images from the Mariner, Viking and Mars Global Surveyor missions, have shown geologic features on the martian surface that seem to indicate an earlier period of hydrologic activity. The fact that ancient valley networks and degraded craters have been seen on the martian surface indicates that the early martian climate may have been more Earth-like, with a warmer surface temperature. The presence of liquid water would require a greenhouse effect much larger than needed at present, as the solar constant, S0, was 25% lower 3.8 billion years ago when the channels are thought to have formed (1,2). Previous calculations have shown that gaseous CO2 and H2O alone could not have warmed the martian surface to the temperature needed to account for the presence of liquid water (3). It has been hypothesized that a CO2-H2O atmosphere could keep early Mars warm if it was filled with CO2 ice clouds in the upper martian troposphere (4). Obtaining mean martian surface temperatures above 273 K would require nearly 100% cloud cover, a condition that is unrealistic for condensation clouds on early Mars. Any reduction in cloud cover makes it difficult to achieve warm martian surface temperatures except at high pressures and CO2 clouds could cool the martian surface if they were low and optically thick (5). CO2 and CH4 have been suggested as important greenhouse gases on the early Earth. Our research focuses on the effects of increased concentrations of atmospheric greenhouse gases on the surface temperature of early Mars, with emphasis on the reduced greenhouse gas, CH4. To investigate the possible warming effect of CH4, we modified a one-dimensional, radiative-convective climate model used in previous studies of the early martian climate (5). New cloud-free temperature profiles for various surface pressures and CH4 mixing

  1. Resource Letter: GW-1: Global warming

    NASA Astrophysics Data System (ADS)

    Firor, John W.

    1994-06-01

    This Resource Letter provides a guide to the literature on the possibility of a human-induced climate change—a global warming. Journal articles and books are cited for the following topics: the Greenhouse Effect, sources of infrared-trapping gases, climate models and their uncertainties, verification of climate models, past climate changes, and economics, ethics, and politics of policy responses to climate change. [The letter E after an item indicates elementary level or material of general interest to persons becoming informed in the field. The letter I, for intermediate level, indicates material of somewhat more specialized nature, and the letter A indicates rather specialized or advanced material.

  2. Scientists' Views about Attribution of Global Warming

    NASA Astrophysics Data System (ADS)

    Verheggen, Bart; Strengers, Bart; Cook, John; van Dorland, Rob; Vringer, Kees; Peters, Jeroen; Visser, Hans; Meyer, Leo

    2015-04-01

    What do scientists think? That is an important question when engaging in science communication, in which an attempt is made to communicate the scientific understanding to a lay audience. To address this question we undertook a large and detailed survey among scientists studying various aspects of climate change , dubbed "perhaps the most thorough survey of climate scientists ever" by well-known climate scientist and science communicator Gavin Schmidt. Among more than 1800 respondents we found widespread agreement that global warming is predominantly caused by human greenhouse gases. This consensus strengthens with increased expertise, as defined by the number of self-reported articles in the peer-reviewed literature. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), agreed that anthropogenic greenhouse gases are the dominant cause of recent global warming, i.e. having contributed more than half of the observed warming. With this survey we specified what the consensus position entails with much greater specificity than previous studies. The relevance of this consensus for science communication will be discussed. Another important result from our survey is that the main attribution statement in IPCC's fourth assessment report (AR4) may lead to an underestimate of the greenhouse gas contribution to warming, because it implicitly includes the lesser known masking effect of cooling aerosols. This shows the importance of the exact wording in high-profile reports such as those from IPCC in how the statement is perceived, even by fellow scientists. The phrasing was improved in the most recent assessment report (AR5). Respondents who characterized the human influence on climate as insignificant, reported having the most frequent media coverage regarding their views on climate change. This shows that contrarian opinions are amplified in the media in relation to their prevalence in the scientific community. This

  3. Global warming and carbon dioxide through sciences.

    PubMed

    Florides, Georgios A; Christodoulides, Paul

    2009-02-01

    Increased atmospheric CO(2)-concentration is widely being considered as the main driving factor that causes the phenomenon of global warming. This paper attempts to shed more light on the role of atmospheric CO(2) in relation to temperature-increase and, more generally, in relation to Earth's life through the geological aeons, based on a review-assessment of existing related studies. It is pointed out that there has been a debate on the accuracy of temperature reconstructions as well as on the exact impact that CO(2) has on global warming. Moreover, using three independent sets of data (collected from ice-cores and chemistry) we perform a specific regression analysis which concludes that forecasts about the correlation between CO(2)-concentration and temperature rely heavily on the choice of data used, and one cannot be positive that indeed such a correlation exists (for chemistry data) or even, if existing (for ice-cores data), whether it leads to a "severe" or a "gentle" global warming. A very recent development on the greenhouse phenomenon is a validated adiabatic model, based on laws of physics, forecasting a maximum temperature-increase of 0.01-0.03 degrees C for a value doubling the present concentration of atmospheric CO(2). Through a further review of related studies and facts from disciplines like biology and geology, where CO(2)-change is viewed from a different perspective, it is suggested that CO(2)-change is not necessarily always a negative factor for the environment. In fact it is shown that CO(2)-increase has stimulated the growth of plants, while the CO(2)-change history has altered the physiology of plants. Moreover, data from palaeoclimatology show that the CO(2)-content in the atmosphere is at a minimum in this geological aeon. Finally it is stressed that the understanding of the functioning of Earth's complex climate system (especially for water, solar radiation and so forth) is still poor and, hence, scientific knowledge is not at a level to

  4. Day and night warming have different effect on root lifespan

    NASA Astrophysics Data System (ADS)

    Bai, W. M.; Xia, J. Y.; Wan, S. Q.; Zhang, W. H.; Li, L. H.

    2012-01-01

    Roots are key components of C cycling in terrestrial ecosystems and play an important role in the regulation of response of terrestrial ecosystems to global climate warming, which is predicted to occur with greater warming magnitudes at night than during daytime across different regions on the Earth. However, there has been no detailed study to investigate the effect of asymmetrical warming on root dynamics at the level of terrestrial ecosystems. To understand the effects of day and night warming on root lifespan in the semiarid temperate steppe in northern China, a field study with a full factorial design including control, day warming, night warming and continuous warming was conducted using modified rhizotron technique during three growing seasons in 2007-2009. Our results show that day, night and continuous warming had different effects on longevity of roots born in spring, summer and autumn, and that day warming significantly prolonged overall lifespan for the roots born in the three growing seasons, while night warning had no effect on overall lifespan. Day and night warming had different effects on root non-structural carbohydrate content, suggesting that allocation of photoassimilate may account for the differential responses of root lifespan to day and night warming. These results differ from other processes associated with ecosystems C cycle such as total ecosystem productivity, net ecosystem productivity and soil respiration. Our findings highlight that it is essential to incorporate the differential effects of day and night warming on root dynamics into simulating and predicting the responses and feedbacks of terrestrial ecosystems C cycling to global warming.

  5. Global warming and thermohaline circulation stability.

    PubMed

    Wood, Richard A; Vellinga, Michael; Thorpe, Robert

    2003-09-15

    The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future.

  6. Photochemical aerosols in warm exoplanetary atmospheres

    NASA Astrophysics Data System (ADS)

    Imanaka, Hiroshi; Smith, Mark A.; McKay, Christopher P.; Cruikshank, Dale P.; Marley, Mark S.

    2016-10-01

    Recent transit observations of exoplanets have demonstrated the possibility of a wide prevalence of haze/cloud layers at high altitudes. Hydrocarbon photochemical haze could be the candidate for such haze particles on warm sub-Neptunes, but the lack of evidence for methane poses a puzzle for such hydrocarbon photochemical haze. The CH4/CO ratios in planetary atmospheres vary substantially from their temperature and dynamics. We have conducted a series of laboratory simulations to investigate how atmospheric compositions, specifically CH4/CO ratios, affect the haze production rates and their optical properties. The mass production rates in the H2-CH4-CO gas mixtures are rather insensitive to the CH4/CO ratios larger than at 0.3. Significant formation of solid material is observed in a H2-CO gas mixture even without CH4. The complex refractive indices of the aerosol analogue from the H2-CO gas mixture show strong absorption at the visible/near-IR wavelengths. These experimental facts imply that substantial carbonaceous aerosols may be generated in warm H2-CO-CH4 exoplanetary atmospheres, and that it might be responsible for the observed dark albedos at the visible wavelengths.

  7. Global warming and cyanobacterial harmful algal blooms.

    PubMed

    Paul, Valerie J

    2008-01-01

    The Earth and the oceans have warmed significantly over the past four decades, providing evidence that the Earth is undergoing long-term climate change. Increasing temperatures and changing rainfall patterns have been documented. Cyanobacteria have a long evolutionary history, with their first occurrence dating back at least 2.7 billion years ago. Cyanobacteria often dominated the oceans after past mass extinction events. They evolved under anoxic conditions and are well adapted to environmental stress including exposure to UV, high solar radiation and temperatures, scarce and abundant nutrients. These environmental conditions favor the dominance of cyanobacteria in many aquatic habitats, from freshwater to marine ecosystems. A few studies have examined the ecological consequences of global warming on cyanobacteria and other phytoplankton over the past decades in freshwater, estuarine, and marine environments, with varying results. The responses of cyanobacteria to changing environmental patterns associated with global climate change are important subjects for future research. Results of this research will have ecological and biogeochemical significance as well as management implications.

  8. Identifying the Molecular Origin of Global Warming

    NASA Technical Reports Server (NTRS)

    Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.

    2009-01-01

    We have investigated the physical characteristics of greenhouse gases (GHGs) to assess which properties are most important in determining the efficiency of a GHG. Chlorofluorcarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen fluorides, and various other known atmospheric trace molecules have been included in this study. Compounds containing the halogens F or Cl have in common very polar X-F or X-Cl bonds, particularly the X-F bonds. It is shown that as more F atoms bond to the same central atom, the bond dipoles become larger as a result of the central atom becoming more positive. This leads to a linear increase in the total or integrated XF bond dipole derivatives for the molecule, which leads to a non-linear (quadratic) increase in infrared (IR) intensity. Moreover, virtually all of the X-F bond stretches occur in the atmospheric IR window as opposed to X-H stretches, which do not occur in the atmospheric window. It is concluded that molecules possessing several F atoms will always have a large radiative forcing parameter in the calculation of their global warming potential. Some of the implications for global warming and climate change are discussed.

  9. Acting green elicits a literal warm glow

    NASA Astrophysics Data System (ADS)

    Taufik, Danny; Bolderdijk, Jan Willem; Steg, Linda

    2015-01-01

    Environmental policies are often based on the assumption that people only act environmentally friendly if some extrinsic reward is implicated, usually money. We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicits psychological rewards in the form of positive feelings, a phenomenon known as warm glow. Given the fact that people's psychological state may affect their thermal state, we expected that this warm glow could express itself quite literally: people who act environmentally friendly may perceive the temperature to be higher. In two studies, we found that people who learned they acted environmentally friendly perceived a higher temperature than people who learned they acted environmentally unfriendly. The underlying psychological mechanism pertains to the self-concept: learning you acted environmentally friendly signals to yourself that you are a good person. Together, our studies show that acting environmentally friendly can be psychologically rewarding, suggesting that appealing to intrinsic rewards can be an alternative way to encourage pro-environmental actions.

  10. Warming alters the metabolic balance of ecosystems

    PubMed Central

    Yvon-Durocher, Gabriel; Jones, J. Iwan; Trimmer, Mark; Woodward, Guy; Montoya, Jose M.

    2010-01-01

    The carbon cycle modulates climate change, via the regulation of atmospheric CO2, and it represents one of the most important services provided by ecosystems. However, considerable uncertainties remain concerning potential feedback between the biota and the climate. In particular, it is unclear how global warming will affect the metabolic balance between the photosynthetic fixation and respiratory release of CO2 at the ecosystem scale. Here, we present a combination of experimental field data from freshwater mesocosms, and theoretical predictions derived from the metabolic theory of ecology to investigate whether warming will alter the capacity of ecosystems to absorb CO2. Our manipulative experiment simulated the temperature increases predicted for the end of the century and revealed that ecosystem respiration increased at a faster rate than primary production, reducing carbon sequestration by 13 per cent. These results confirmed our theoretical predictions based on the differential activation energies of these two processes. Using only the activation energies for whole ecosystem photosynthesis and respiration we provide a theoretical prediction that accurately quantified the precise magnitude of the reduction in carbon sequestration observed experimentally. We suggest the combination of whole-ecosystem manipulative experiments and ecological theory is one of the most promising and fruitful research areas to predict the impacts of climate change on key ecosystem services. PMID:20513719

  11. Global warming and thermohaline circulation stability.

    PubMed

    Wood, Richard A; Vellinga, Michael; Thorpe, Robert

    2003-09-15

    The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future. PMID:14558904

  12. Soil crusts to warm the planet

    NASA Astrophysics Data System (ADS)

    Garcia-Pichel, Ferran; Couradeau, Estelle; Karaoz, Ulas; da Rocha Ulisses, Nunes; Lim Hsiao, Chiem; Northen, Trent; Brodie, Eoin

    2016-04-01

    Soil surface temperature, an important driver of terrestrial biogeochemical processes, depends strongly on soil albedo, which can be significantly modified by factors such as plant cover. In sparsely vegetated lands, the soil surface can also be colonized by photosynthetic microbes that build biocrust communities. We used concurrent physical, biochemical and microbiological analyses to show that mature biocrusts can increase surface soil temperature by as much as 10 °C through the accumulation of large quantities of a secondary metabolite, the microbial sunscreen scytonemin, produced by a group of late-successional cyanobacteria. Scytonemin accumulation decreases soil albedo significantly. Such localized warming had apparent and immediate consequences for the crust soil microbiome, inducing the replacement of thermosensitive bacterial species with more thermotolerant forms. These results reveal that not only vegetation but also microorganisms are a factor in modifying terrestrial albedo, potentially impacting biosphere feedbacks on past and future climate, and call for a direct assessment of such effects at larger scales. Based on estimates of the global biomass of cyanobacteria in soil biocrusts, one can easily calculate that there must currently exist about 15 million metric tons of scytonemin at work, warming soil surfaces worldwide

  13. Global warming and thermohaline circulation stability

    NASA Astrophysics Data System (ADS)

    Wood, Richard A.; Vellinga, Michael; Thorpe, Robert

    2003-09-01

    The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future.

  14. Multicompartment Liquid-Cooling/Warming Protective Garments

    NASA Technical Reports Server (NTRS)

    Koscheyev, Victor S.; Leon, Gloria R.; Dancisak, Michael J.

    2005-01-01

    Shortened, multicompartment liquid-cooling / warming garments (LCWGs) for protecting astronauts, firefighters, and others at risk of exposure to extremes of temperature are undergoing development. Unlike prior liquid-circulation thermal-protection suits that provide either cooling or warming but not both, an LCWG as envisioned would provide cooling at some body locations and/or heating at other locations, as needed: For example, sometimes there is a need to cool the body core and to heat the extremities simultaneously. An LCWG garment of the type to be developed is said to be shortened because the liquid-cooling and - heating zones would not cover the whole body and, instead, would cover reduced areas selected for maximum heating and cooling effectiveness. Physiological research is under way to provide a rational basis for selection of the liquid-cooling and -heating areas. In addition to enabling better (relative to prior liquid-circulation garments) balancing of heat among different body regions, the use of selective heating and cooling in zones would contribute to a reduction in the amount of energy needed to operate a thermal-protection suit.

  15. A warm air poultry brooding system

    SciTech Connect

    Nulte, W.H.

    1980-12-01

    As the energy crisis escalated during the mid-70's, it became apparent that energy intensive industries must seek alternate fuel sources. Georgia Tech realized that one of these industries was the poultry industry. Consequently, a demonstration project of a wood-fired, warm air poultry brooding system was designed and built. Since its completion in mid-1978, the system has demonstrated considerable cost savings as well as being a very functional and reliable system. The system consists of 3 main components--a wood burning furnace, a supply distribution and return duct, and 20 flexible ducts which simulate the function of the propane brooders by providing warm air close to the ground. A separate structure houses the furnace and wood supply. This house is located at the midpoint of the growout house to allow symmetrical and naturally balanced air distribution. Since the system became operational, 16 flocks of birds have been brooded. During this time, wood usage has averaged approximately 30 cords per year while in a neighboring house, that is used as a control house, the propane usage has averaged 3,800 gallons per year. In the area of Georgia where the demonstration project is located, the cost of fuelwood has remained stable over the last 2 years, whereas the price of propane has continually increased. Thus the grower has the benefit of constantly increasing cost savings while utilizing a renewable resource as fuel.

  16. Separating Contributions from Anthropogenic Warming and from Natural Oscillations to Global Warming

    NASA Astrophysics Data System (ADS)

    Konrad Stips, Adolf; Macias, Diego; Garcia-Gorriz, Elisa

    2014-05-01

    During the past five decades, global air temperatures have been warming at a rather high rate (IPCC-2013) resulting in scientific and social concern. This warming trend is observed in field data sampling and model simulations and affects both air temperatures over land and over the ocean. However, the warming rate changes with time and this has led to question the causes underlying the observed trends. Here, we analyze recent measured and modeled data on global mean surface air temperature anomalies (GMTA) covering the last 160 years using spectral techniques. The spectral analysis of the measured data does show a strong secular trend (ST) and a clear multidecadal sinusoidal oscillation (MDV) that resembles the Atlantic Multidecadal Oscillation (AMO). The observed acceleration of the warming during the period from 1970 to 2000 therefore appears to be caused by a superimposition of anthropogenic-induced warming (~60%) with the positive phase of a multidecadal oscillation (~40%), while the recent slowdown (hiatus) of this tendency is likely due to a shift in the MDV phase. It has been proposed that this change in the MDV phase could mask the effect of global warming in the forthcoming decades and our analysis indicates that this is quite likely, the current hiatus being already a manifestation of this phenomenon. Most current generation global circulation models (CMIP5) do not reproduce this MDV and are missing the actual temperature hiatus. Therefore, it is less likely that such models could correctly forecast the temperature evolution during the coming decades. We propose here to use the climate dynamics that is inherent in the GMTA data to forecast temperatures until 2100. These forecasts, based on the analyzed secular trend and the multidecadal oscillations are indeed capable of reproducing the actual hiatus and generally result, in comparison to CMIP5 forecasts, in much lower temperature increases for 2100 of only about 1oC. Global mean air temperatures could be

  17. Microbial communities respond to experimental warming, but site matters.

    PubMed

    Cregger, Melissa A; Sanders, Nathan J; Dunn, Robert R; Classen, Aimée T

    2014-01-01

    Because microorganisms are sensitive to temperature, ongoing global warming is predicted to influence microbial community structure and function. We used large-scale warming experiments established at two sites near the northern and southern boundaries of US eastern deciduous forests to explore how microbial communities and their function respond to warming at sites with differing climatic regimes. Soil microbial community structure and function responded to warming at the southern but not the northern site. However, changes in microbial community structure and function at the southern site did not result in changes in cellulose decomposition rates. While most global change models rest on the assumption that taxa will respond similarly to warming across sites and their ranges, these results suggest that the responses of microorganisms to warming may be mediated by differences across the geographic boundaries of ecosystems.

  18. Temperature and size variabilities of the Western pacific warm pool.

    PubMed

    Yan, X H; Ho, C R; Zheng, Q; Klemas, V

    1992-12-01

    Variabilities in sea-surface temperature and size of the Western Pacific Warm Pool were tracked with 10 years of satellite multichannel sea-surface temperature observations from 1982 to 1991. The results show that both annual mean sea-surface temperature and the size of the warm pool increased from 1983 to 1987 and fluctuated after 1987. Possible causes of these variations include solar irradiance variabilities, EI Niño-Southern Oscillation events, volcanic activities, and global warming.

  19. The impact of global warming on Mount Everest.

    PubMed

    Moore, G W K; Semple, John L

    2009-01-01

    Global warming impacts a wide range of human activities and ecosystems. One unanticipated consequence of the warming is an increase in barometric pressure throughout the troposphere. Mount Everest's extreme height and resulting low barometric pressure places humans near its summit in an extreme state of hypoxia. Here we quantify the degree with which this warming is increasing the barometric pressure near Everest's summit and argue that it is of such a magnitude as to make the mountain, over time, easier to climb.

  20. Deglacial Warming and Wetting of Northern Alaska

    NASA Astrophysics Data System (ADS)

    Daniels, W.; Russell, J. M.; Longo, W. M.; Giblin, A. E.; Holland-Stergar, P.; Morrill, C.; Huang, Y.

    2015-12-01

    Aeolian sand dunes swept across northern Alaska during the last glacial maximum. Today, summer temperatures are moderate and soils can remain waterlogged all summer long. How did the transition from a cold and dry glacial to a warm and wet interglacial take place? To answer this question we reconstructed temperature and precipitation changes during the last deglaciation using biomarker hydrogen isotopes from a new 28,000 year-long sediment core from Lake E5, located in the central Brooks Range of Alaska. We use terrestrial leaf waxes (dDterr, C28-acid), informed by dD measurements of modern vegetation, to infer dD of precipitation, an indicator of relative temperature change. Biomarkers from aquatic organisms (dDaq, C18-acid) are used as a proxy for lake water isotopes. The offset between the two (eterr-aq) is used to infer relative changes in evaporative enrichment of lake water, and by extension, moisture balance. dDterr during the last glacial period was -282‰ compared to -258‰ during the Holocene, suggesting a 5.6 ± 2.7 °C increase in summer temperature using the modern local temperature-dD relationship. Gradual warming began at ~18.5 ka, and temperature increased abruptly at 11.5 ka, at the end of the Younger Dryas. Warming peaked in the early Holocene from 11.5 to 9.1 ka, indicating a Holocene thermal maximum associated with peak summer insolation. The eterr-aq supports a dry LGM and moist Holocene. Other sediment proxies (TIC, TOC, redox-sensitive elements) support the eterr-aq, and reveal a shift to more positive P-E beginning around 17 ka, suggesting rising temperature led increases in precipitation during the last deglaciation. Moreover, differing patterns of dDterr and eterr-aq during the deglaciation suggest that the relationship between temperature and precipitation changed through time. Such decoupling, likely due to regional atmospheric reorganization as the Laurentide ice sheet waned, illustrates the importance of atmospheric dynamics in

  1. Drought under Global Warming: A Review

    NASA Astrophysics Data System (ADS)

    Dai, A.

    2011-12-01

    One of the big concerns associated with global warming is the potential change to land surface moisture conditions that could have a huge impact on agriculture, freshwater resources, and many other aspects of our society and the environment. How drought has changed during recent past and how it might change in the coming decades is increasingly becoming a great concern as global warming continues and more severe droughts are reported in the media. In this presentation, I will provide an overview, based on my own and others' work, of how drought has changed in the last several centuries and during recent decades over many regions around the world based on historical records, and how it might change in the coming decades based on IPCC AR4 model-predicted climate changes. I will present results from analyses of changes in precipitation, streamflow, soil moisture, and (improved) Palmer Drought Severity Index (PDSI) to show that aridity has increased during the last 50-60 years over many land areas, and rapid warming since the 1980s has contributed significantly to this drying. The PDSI (with improved evapotranspiration estimates) calculated from the AR4 multi-model predicted future climate suggests severe drying in the next 20-50 years over most land areas except the northern high-latitudes and parts of Asia. This drying pattern is consistent with other analyses of model-predicted soil moisture and precipitation changes. Although the quantitative interpretation of the future PDSI values may need to be cautious, combined with the other analyses, the PDSI result points to a dire situation with more severe to extreme droughts in the coming decades over the continental U.S., most of Africa and South America, Australia, southern Europe, and western and southeastern Asia. Changes in precipitation play an important role over many land areas, but enhanced evaporation due to increased radiative heating is also a major factor for the model-predicted drying. For more details, see

  2. Middle-Atmosphere Polar Warming at Mars

    NASA Astrophysics Data System (ADS)

    McDunn, T. L.; Bougher, S. W.; Kleinboehl, A.; Forget, F.; Murphy, J. R.; Smith, M. D.; Mischna, M. A.

    2011-12-01

    Polar Warming (PW) is a dynamical feature of the Martian atmosphere that consists of a temperature enhancement over mid-to-high latitudes during winter, spring, and autumn. It produces a reversal of the meridional temperature gradient and temperature inversions over mid-to-high latitudes. This phenomenon is the result of a global Hadley circulation which is a thermally-direct response to diabatic forcing caused by: (a) differential insolation, and (b) absorption of solar infrared radiation by suspended dust [1-4]. Previous studies of PW [5-9] have been limited by data paucity. Consequently, several important aspects of PW climatology have gone unknown. Now, sufficient data is available for in-depth characterization of the structure and variability of this phenomenon in the middle atmosphere [manuscript in preparation]. In this paper we define a warming index and characterize PW as observed by MCS/MRO, SPICAM/Mars Express, and the accelerometer experiments that flew on MGS, Mars Odyssey, and MRO. During most seasons, PW manifests between p = 1-10 Pa and the top of the MCS dataset, and during seasons where SPICAM and ACC data are available, warming often persists through the extent of these data as well (i.e., up to p = 1.0 x 10-4 Pa). PW maximizes in the vertical between p = 1.9 to 0.5 Pa. We find the latitude of maximum temperature tends to move pole-ward with decreasing pressure, indicating a pole-ward slant with height of the descending branch of the Hadley cell. We find PW tends to be stronger on the nightside than on the dayside. As expected from previous studies, we find PW is stronger during northern winter solstice (Ls = 270°) than during southern winter solstice (Ls = 90°). Interestingly, however, we find PW in both the northern hemisphere and the southern hemisphere is stronger during Ls = 180° than during other seasons. This is unexpected because: (a) early studies focused on PW as strictly a winter phenomenon, and (b) dust optical depth is generally

  3. 100 LPW 800 Lm Warm White LED

    SciTech Connect

    Sun, Decai

    2010-10-31

    An illumination grade warm white (WW) LED, having correlated color temperature (CCT) between 2800 K and 3500K and capable of producing 800 lm output at 100 lm/W, has been developed in this program. The high power WW LED is an ideal source for use as replacement for incandescent, and Halogen reflector and general purpose lamps of similar lumen value. Over the two year period, we have made following accomplishments: developed a high power warm white LED product and made over 50% improvements in light output and efficacy. The new high power WW LED product is a die on ceramic surface mountable LED package. It has four 1x1 mm{sup 2} InGaN pump dice flip chip attached to a ceramic submount in 2x2 array, covered by warm white phosphor ceramic platelets called Lumiramica and an overmolded silicone lens encapsulating the LED array. The performance goal was achieved through breakthroughs in following key areas: (1) High efficiency pump LED development through pump LED active region design and epi growth quality improvement (funded by internal programs). (2) Increase in injection efficiency (IE) represented by reduction in forward voltage (V{sub f}) through the improvement of the silver-based p-contact and a reduction in spreading resistance. The injection efficiency was increased from 80% at the start of the program to 96% at the end of the program at 700 mA/mm{sup 2}. (3) Improvement in thermal design as represented by reduction in thermal resistance from junction to case, through improvement of the die to submount connection in the thin film flip chip (TFFC) LED and choosing the submount material of high thermal conductivity. A thermal resistance of 1.72 K/W was demonstrated for the high power LED package. (4) Improvement in extraction efficiency from the LED package through improvement of InGaN die level and package level optical extraction efficiency improvement. (5) Improvement in phosphor system efficiency by improving the lumen equivalent (LE) and phosphor package

  4. Global warming and neurodegenerative disorders: speculations on their linkage.

    PubMed

    Habibi, Laleh; Perry, George; Mahmoudi, Morteza

    2014-01-01

    Climate change is having considerable impact on biological systems. Eras of ice ages and warming shaped the contemporary earth and origin of creatures including humans. Warming forces stress conditions on cells. Therefore, cells evolved elaborate defense mechanisms, such as creation of heat shock proteins, to combat heat stress. Global warming is becoming a crisis and this process would yield an undefined increasing rate of neurodegenerative disorders in future decades. Since heat stress is known to have a degenerative effects on neurons and, conversely, cold conditions have protective effect on these cells, we hypothesize that persistent heat stress forced by global warming might play a crucial role in increasing neurodegenerative disorders.

  5. Sustaining effect of soil warming on organic matter decomposition

    NASA Astrophysics Data System (ADS)

    Hou, Ruixing; Ouyang, Zhu; Dorodnikov, Maxim; Wilson, Glenn; Kuzyakov, Yakov

    2015-04-01

    Global warming affects various parts of carbon (C) cycle including acceleration of soil organic matter (SOM) decomposition with strong feedback to atmospheric CO2 concentration. Despite many soil warming studies showed changes of microbial community structure, only very few were focused on sustainability of soil warming on microbial activity associated with SOM decomposition. Two alternative hypotheses: 1) acclimation because of substrate exhaustion and 2) sustaining increase of microbial activity with accelerated decomposition of recalcitrant SOM pools were never proven under long term field conditions. This is especially important in the nowadays introduced no-till crop systems leading to redistribution of organic C at the soil surface, which is much susceptible to warming effects than the rest of the profile. We incubated soil samples from a four-year warming experiment with tillage (T) and no-tillage (NT) practices under three temperatures: 15, 21, and 27 °C, and related the evolved total CO2 efflux to changes of organic C pools. Warmed soils released significantly more CO2 than the control treatment (no warming) at each incubation temperature, and the largest differences were observed under 15 °C (26% increase). The difference in CO2 efflux from NT to T increase with temperature showing high vulnerability of C stored in NT to soil warming. The Q10 value reflecting the sensitivity of SOM decomposition to warming was lower for warmed than non-warmed soil indicating better acclimation of microbes or lower C availability during long term warming. The activity of three extracellular enzymes: β-glucosidase, chitinase, sulphatase, reflecting the response of C, N and S cycles to warming, were significantly higher under warming and especially under NT compared to two other respective treatments. The CO2 released during 2 months of incubation consisted of 85% from recalcitrant SOM and the remaining 15% from microbial biomass and extractable organic C based on the

  6. Mechanisms for stronger warming over drier ecoregions observed since 1979

    NASA Astrophysics Data System (ADS)

    Zhou, Liming; Chen, Haishan; Hua, Wenjian; Dai, Yongjiu; Wei, Nan

    2016-02-01

    Previous research found that the warming rate observed for the period 1979-2012 increases dramatically with decreasing vegetation greenness over land between 50°S and 50°N, with the strongest warming rate seen over the driest regions such as the Sahara desert and the Arabian Peninsula, suggesting warming amplification over deserts. To further this finding, this paper explores possible mechanisms for this amplification by analyzing observations, reanalysis data and historical simulations of global coupled atmosphere-ocean general circulation models. We examine various variables, related to surface radiative forcing, land surface properties, and surface energy and radiation budget, that control the warming patterns in terms of large-scale ecoregions. Our results indicate that desert amplification is likely attributable primarily to enhanced longwave radiative forcing associated with a stronger water vapor feedback over drier ecoregions in response to the positive global-scale greenhouse gas forcing. This warming amplification and associated downward longwave radiation at the surface are reproduced by historical simulations with anthropogenic and natural forcings, but are absent if only natural forcings are considered, pointing to new potential fingerprints of anthropogenic warming. These results suggest a fundamental pattern of global warming over land that depend on the dryness of ecosystems in mid- and low- latitudes, likely reflecting primarily the first order large-scale thermodynamic component of global warming linked to changes in the water and energy cycles over different ecosystems. This finding may have important implications in interpreting global warming patterns and assessing climate change impacts.

  7. Global warming and neurodegenerative disorders: speculations on their linkage

    PubMed Central

    Habibi, Laleh; Perry, George; Mahmoudi, Morteza

    2014-01-01

    Climate change is having considerable impact on biological systems. Eras of ice ages and warming shaped the contemporary earth and origin of creatures including humans. Warming forces stress conditions on cells. Therefore, cells evolved elaborate defense mechanisms, such as creation of heat shock proteins, to combat heat stress. Global warming is becoming a crisis and this process would yield an undefined increasing rate of neurodegenerative disorders in future decades. Since heat stress is known to have a degenerative effects on neurons and, conversely, cold conditions have protective effect on these cells, we hypothesize that persistent heat stress forced by global warming might play a crucial role in increasing neurodegenerative disorders. PMID:25671171

  8. Southern Ocean warming delayed by circumpolar upwelling and equatorward transport

    NASA Astrophysics Data System (ADS)

    Armour, Kyle C.; Marshall, John; Scott, Jeffery R.; Donohoe, Aaron; Newsom, Emily R.

    2016-07-01

    The Southern Ocean has shown little warming over recent decades, in stark contrast to the rapid warming observed in the Arctic. Along the northern flank of the Antarctic Circumpolar Current, however, the upper ocean has warmed substantially. Here we present analyses of oceanographic observations and general circulation model simulations showing that these patterns--of delayed warming south of the Antarctic Circumpolar Current and enhanced warming to the north--are fundamentally shaped by the Southern Ocean's meridional overturning circulation: wind-driven upwelling of unmodified water from depth damps warming around Antarctica; greenhouse gas-induced surface heat uptake is largely balanced by anomalous northward heat transport associated with the equatorward flow of surface waters; and heat is preferentially stored where surface waters are subducted to the north. Further, these processes are primarily due to passive advection of the anomalous warming signal by climatological ocean currents; changes in ocean circulation are secondary. These findings suggest the Southern Ocean responds to greenhouse gas forcing on the centennial, or longer, timescale over which the deep ocean waters that are upwelled to the surface are warmed themselves. It is against this background of gradual warming that multidecadal Southern Ocean temperature trends must be understood.

  9. Plant community responses to experimental warming across the tundra biome.

    PubMed

    Walker, Marilyn D; Wahren, C Henrik; Hollister, Robert D; Henry, Greg H R; Ahlquist, Lorraine E; Alatalo, Juha M; Bret-Harte, M Syndonia; Calef, Monika P; Callaghan, Terry V; Carroll, Amy B; Epstein, Howard E; Jónsdóttir, Ingibjörg S; Klein, Julia A; Magnússon, Borgthór; Molau, Ulf; Oberbauer, Steven F; Rewa, Steven P; Robinson, Clare H; Shaver, Gaius R; Suding, Katharine N; Thompson, Catharine C; Tolvanen, Anne; Totland, Ørjan; Turner, P Lee; Tweedie, Craig E; Webber, Patrick J; Wookey, Philip A

    2006-01-31

    Recent observations of changes in some tundra ecosystems appear to be responses to a warming climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, including warming; however, most studies were limited to a single location and were of short duration and based on a variety of experimental designs. In addition, comparisons among studies are difficult because a variety of techniques have been used to achieve experimental warming and different measurements have been used to assess responses. We used metaanalysis on plant community measurements from standardized warming experiments at 11 locations across the tundra biome involved in the International Tundra Experiment. The passive warming treatment increased plant-level air temperature by 1-3 degrees C, which is in the range of predicted and observed warming for tundra regions. Responses were rapid and detected in whole plant communities after only two growing seasons. Overall, warming increased height and cover of deciduous shrubs and graminoids, decreased cover of mosses and lichens, and decreased species diversity and evenness. These results predict that warming will cause a decline in biodiversity across a wide variety of tundra, at least in the short term. They also provide rigorous experimental evidence that recently observed increases in shrub cover in many tundra regions are in response to climate warming. These changes have important implications for processes and interactions within tundra ecosystems and between tundra and the atmosphere.

  10. Global warming and changes in ocean circulation

    SciTech Connect

    Duffy, P.B.; Caldeira, K.C.

    1998-02-01

    This final report provides an overview of the goals and accomplishments of this project. Modeling and observational work has raised the possibility that global warming may cause changes in the circulation of the ocean. If such changes would occur they could have important climatic consequences. The first technical goal of this project was to investigate some of these possible changes in ocean circulation in a quantitative way, using a state-of -the-art numerical model of the ocean. Another goal was to develop our ocean model, a detailed three-dimensional numerical model of the ocean circulation and ocean carbon cycles. A major non-technical goal was to establish LLNL as a center of excellence in modelling the ocean circulation and carbon cycle.

  11. Ecologic simulation of warm water aquaculture ponds

    SciTech Connect

    Piedrahitu, R.H.; Brune, D.E.; Orlob, G.T.; Tchobanoglous, G.

    1983-06-01

    A generalized ecologic model of a fertilized warm-water aquaculture pond is under development. The model is intended to represent the pond ecosystem and its response to external stimuli. The major physical, chemical and biological processes and parameters are included in the model. A total of 19 state variables are included in the model (dissolved oxygen, alkalinity, pH, ammonia, phytoplankton, etc.). The model is formulated as a system of mass balance equations. The equations include stimulatory and inhibitory effects of environmental parameters on processes taking place in the pond. The equations may be solved for the entire growth period and diurnal as well as seasonal fluctuations may be identified. The ultimate objective of the model is to predict the fish biomass that can be produced in a pond under a given set of environmental conditions.

  12. Microwave sounding units and global warming

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L.; Keihm, Stephen J.

    1991-01-01

    A recent work of Spencer and Christy (1990) on precise monitoring of global temperature trends from satellites is critically examined. It is tentatively concluded in the present comment that remote sensing using satellite microwave radiometers can in fact provide a means for the monitoring of troposphere-averaged air temperature. However, for this to be successful more than one decade of data will be required to overcome the apparent inherent variability of global average air temperature. It is argued that the data set reported by Spencer and Christy should be subjected to careful review before it is interpreted as evidence of the presence or absence of global warming. In a reply, Christy provides specific responses to the commenters' objections.

  13. Seasonal flows on warm Martian slopes

    USGS Publications Warehouse

    McEwen, Alfred S.; Ojha, Lujendra; Dundas, Colin M.; Mattson, Sarah S.; Byrne, Shane; Wray, James J.; Cull, Selby C.; Murchie, Scott L.; Thomas, Nicolas; Gulick, Virginia C.

    2011-01-01

    Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

  14. Seasonal flows on warm Martian slopes

    USGS Publications Warehouse

    McEwen, A.S.; Ojha, L.; Dundas, C.M.; Mattson, S.S.; Byrne, S.; Wray, J.J.; Cull, S.C.; Murchie, S.L.; Thomas, N.; Gulick, V.C.

    2011-01-01

    Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25?? to 40??) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48??S to 32??S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ???250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

  15. The Warm-Hot Intergalactic Medium

    NASA Technical Reports Server (NTRS)

    Hayes, Jeffrey (Technical Monitor)

    2005-01-01

    This grant is associated to a 5-year LTSA grant, on "Studying the Largest Reservoir of Baryons in the Universe: The Warm-Hot Intergalactic Medium". The first year of work within this program has been very rich, and has already produced several important results, as detailed in this paper. Table 2 of our original proposal justification, listed the planned year-by-year program, divided into two sub-fields: (A) the study of the z=0 (or Local Group WHIM) system, and (B) the study of the z greater than 0 (i.e- intervening WHIM) systems. For each of the two sub-fields we had planned to analyze, in the first year, a number of archival (Chandra, XMM and FUSE) and new (if observed) sightlines. Moreover, the plan for the z=0 system included the search for new interesting sightlines. We have accomplished all these tasks.

  16. Revaluating ocean warming impacts on global phytoplankton

    NASA Astrophysics Data System (ADS)

    Behrenfeld, Michael J.; O'Malley, Robert T.; Boss, Emmanuel S.; Westberry, Toby K.; Graff, Jason R.; Halsey, Kimberly H.; Milligan, Allen J.; Siegel, David A.; Brown, Matthew B.

    2016-03-01

    Global satellite observations document expansions of the low-chlorophyll central ocean gyres and an overall inverse relationship between anomalies in sea surface temperature and phytoplankton chlorophyll concentrations. These findings can provide an invaluable glimpse into potential future ocean changes, but only if the story they tell is accurately interpreted. Chlorophyll is not simply a measure of phytoplankton biomass, but also registers changes in intracellular pigmentation arising from light-driven (photoacclimation) and nutrient-driven physiological responses. Here, we show that the photoacclimation response is an important component of temporal chlorophyll variability across the global ocean. This attribution implies that contemporary relationships between chlorophyll changes and ocean warming are not indicative of proportional changes in productivity, as light-driven decreases in chlorophyll can be associated with constant or even increased photosynthesis. Extension of these results to future change, however, requires further evaluation of how the multifaceted stressors of a warmer, higher-CO2 world will impact plankton communities.

  17. Seasonal flows on warm Martian slopes.

    PubMed

    McEwen, Alfred S; Ojha, Lujendra; Dundas, Colin M; Mattson, Sarah S; Byrne, Shane; Wray, James J; Cull, Selby C; Murchie, Scott L; Thomas, Nicolas; Gulick, Virginia C

    2011-08-01

    Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

  18. Gravitino Warm Dark Matter with Entropy Production

    SciTech Connect

    Baltz, Edward A.; Murayama, Hitoshi

    2001-08-09

    Gravitinos with a mass in the keV range are an interesting candidate for warm dark matter. Recent measurements of the matter density of the universe and of cosmic structures at the dwarf galaxy scale rule out the simplest gravitino models with thermal freeze-out. We construct a model where the decay of the messenger particles that transmit the supersymmetry breaking to the observable sector generates the required entropy to dilute the gravitino relic density by the required factor of a few to come in line with observations. The model is natural, and requires only that the coupling of the messenger sector to the standard model be set so that the decay happens at the appropriate time.

  19. Global warming, convective threshold and false thermostats

    NASA Astrophysics Data System (ADS)

    Williams, Ian N.; Pierrehumbert, Raymond T.; Huber, Matthew

    2009-11-01

    We demonstrate a theoretically expected behavior of the tropical sea surface temperature probability density function (PDF) in future and past (Eocene) greenhouse climate simulations. To first order this consists of a shift to warmer temperatures as climate warms, without change of shape of the PDF. The behavior is tied to a shift of the temperature for deep convection onset. Consequently, the threshold for appearance of high clouds and associated radiative forcing shifts along with temperature. An excess entropy coordinate provides a reference to which the onset of deep convection is invariant, and gives a compact description of SST changes and cloud feedbacks suitable for diagnostics and as a basis for simplified climate models. The results underscore that the typically skewed appearance of tropical SST histograms, with a sharp drop-off above some threshold value, should not be taken as evidence for tropical thermostats.

  20. Competitive advantage on a warming planet.

    PubMed

    Lash, Jonathan; Wellington, Fred

    2007-03-01

    Whether you're in a traditional smokestack industry or a "clean" business like investment banking, your company will increasingly feel the effects of climate change. Even people skeptical about global warming's dangers are recognizing that, simply because so many others are concerned, the phenomenon has wide-ranging implications. Investors already are discounting share prices of companies poorly positioned to compete in a warming world. Many businesses face higher raw material and energy costs as more and more governments enact policies placing a cost on emissions. Consumers are taking into account a company's environmental record when making purchasing decisions. There's also a burgeoning market in greenhouse gas emission allowances (the carbon market), with annual trading in these assets valued at tens of billions of dollars. Companies that manage and mitigate their exposure to the risks associated with climate change while seeking new opportunities for profit will generate a competitive advantage over rivals in a carbon-constrained future. This article offers a systematic approach to mapping and responding to climate change risks. According to Jonathan Lash and Fred Wellington of the World Resources Institute, an environmental think tank, the risks can be divided into six categories: regulatory (policies such as new emissions standards), products and technology (the development and marketing of climate-friendly products and services), litigation (lawsuits alleging environmental harm), reputational (how a company's environmental policies affect its brand), supply chain (potentially higher raw material and energy costs), and physical (such as an increase in the incidence of hurricanes). The authors propose a four-step process for responding to climate change risk: Quantify your company's carbon footprint; identify the risks and opportunities you face; adapt your business in response; and do it better than your competitors. PMID:17348173

  1. Are Claims of Global Warming Being Suppressed?

    NASA Astrophysics Data System (ADS)

    Crowley, Thomas J.

    2006-02-01

    Over the last few years, I have heard many rumors that climate science relevant to the global warming discussion is being suppressed by the Bush Administration. One cannot do much about third-hand information. However, on 29 January, the New York Times published a front page article on NASA efforts to suppress statements about global warming by James Hansen, director of the NASA Goddard Institute for Space Studies. A claim by one government scientist, though, no matter how distinguished, still requires examples from other scientists before a general conclusion can be drawn about the overall scope of the problem. But if the charges are more widespread, then some government scientists might be reluctant to make such claims, because they might feel that their positions were jeopardized. Therefore, an alternate way may be needed to determine the scope of the issue, while still safeguarding government workers from possible retaliation. -On 30 January, Rep. Sherwood Boehlert (R-N.Y.), chairman of the U.S. House of Representatives Committee on Science, wrote a letter to NASA Administrator Michael Griffin addressing many of the concerns Crowley has raised. Boehlert wrote,``It ought to go without saying that government scientists must be free to describe their scientific conclusions and the implications of those conclusions to their fellow scientists, policymakers and the general public.'' He continued,``Good science cannot long persist in an atmosphere of intimidation. Political figures ought to be reviewing their public statements to make sure they are consistent with the best available science; scientists should not be reviewing their statements to make sure they are consistent with the current political orthodoxy.'' I commend Rep. Boehlert for his quick and clear statement of the importance of unfettered communication of science. -FRED SPILHAUS, Editor

  2. Competitive advantage on a warming planet.

    PubMed

    Lash, Jonathan; Wellington, Fred

    2007-03-01

    Whether you're in a traditional smokestack industry or a "clean" business like investment banking, your company will increasingly feel the effects of climate change. Even people skeptical about global warming's dangers are recognizing that, simply because so many others are concerned, the phenomenon has wide-ranging implications. Investors already are discounting share prices of companies poorly positioned to compete in a warming world. Many businesses face higher raw material and energy costs as more and more governments enact policies placing a cost on emissions. Consumers are taking into account a company's environmental record when making purchasing decisions. There's also a burgeoning market in greenhouse gas emission allowances (the carbon market), with annual trading in these assets valued at tens of billions of dollars. Companies that manage and mitigate their exposure to the risks associated with climate change while seeking new opportunities for profit will generate a competitive advantage over rivals in a carbon-constrained future. This article offers a systematic approach to mapping and responding to climate change risks. According to Jonathan Lash and Fred Wellington of the World Resources Institute, an environmental think tank, the risks can be divided into six categories: regulatory (policies such as new emissions standards), products and technology (the development and marketing of climate-friendly products and services), litigation (lawsuits alleging environmental harm), reputational (how a company's environmental policies affect its brand), supply chain (potentially higher raw material and energy costs), and physical (such as an increase in the incidence of hurricanes). The authors propose a four-step process for responding to climate change risk: Quantify your company's carbon footprint; identify the risks and opportunities you face; adapt your business in response; and do it better than your competitors.

  3. North Atlantic warming during Dansgaard-Oeschger events synchronous with Antarctic warming and out-of-phase with Greenland climate.

    PubMed

    Rasmussen, Tine L; Thomsen, Erik; Moros, Matthias

    2016-01-01

    The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard-Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the south-central Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the differences are apparently linked to perturbations in the ocean circulation pattern. Here we show that surface and intermediate-depth water south of Iceland warmed gradually synchronously with the Antarctic warming and out of phase with the abrupt warming of the Nordic seas and over Greenland. The hinge line between areas showing abrupt and gradual warming was close to the Greenland-Scotland Ridge and the marine system appears to be a 'push-and-pull' system rather than a seesaw system. 'Pull' during the warm interstadials, when convection in the Nordic seas was active; 'push' during the cold stadials, when convection stopped and warm water from the south-central Atlantic pushed northward gradually warming the North Atlantic and Nordic seas. PMID:26847384

  4. North Atlantic warming during Dansgaard-Oeschger events synchronous with Antarctic warming and out-of-phase with Greenland climate

    PubMed Central

    Rasmussen, Tine L.; Thomsen, Erik; Moros, Matthias

    2016-01-01

    The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard-Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the south-central Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the differences are apparently linked to perturbations in the ocean circulation pattern. Here we show that surface and intermediate-depth water south of Iceland warmed gradually synchronously with the Antarctic warming and out of phase with the abrupt warming of the Nordic seas and over Greenland. The hinge line between areas showing abrupt and gradual warming was close to the Greenland-Scotland Ridge and the marine system appears to be a ‘push-and-pull’ system rather than a seesaw system. ‘Pull’ during the warm interstadials, when convection in the Nordic seas was active; ‘push’ during the cold stadials, when convection stopped and warm water from the south-central Atlantic pushed northward gradually warming the North Atlantic and Nordic seas. PMID:26847384

  5. North Atlantic warming during Dansgaard-Oeschger events synchronous with Antarctic warming and out-of-phase with Greenland climate

    NASA Astrophysics Data System (ADS)

    Rasmussen, Tine L.; Thomsen, Erik; Moros, Matthias

    2016-02-01

    The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard-Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the south-central Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the differences are apparently linked to perturbations in the ocean circulation pattern. Here we show that surface and intermediate-depth water south of Iceland warmed gradually synchronously with the Antarctic warming and out of phase with the abrupt warming of the Nordic seas and over Greenland. The hinge line between areas showing abrupt and gradual warming was close to the Greenland-Scotland Ridge and the marine system appears to be a ‘push-and-pull’ system rather than a seesaw system. ‘Pull’ during the warm interstadials, when convection in the Nordic seas was active; ‘push’ during the cold stadials, when convection stopped and warm water from the south-central Atlantic pushed northward gradually warming the North Atlantic and Nordic seas.

  6. Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods.

    PubMed

    Bransburg-Zabary, Sharron; Virozub, Alexander; Mimouni, Francis B

    2015-01-01

    Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60 ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast. PMID:26061694

  7. Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods.

    PubMed

    Bransburg-Zabary, Sharron; Virozub, Alexander; Mimouni, Francis B

    2015-01-01

    Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60 ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast.

  8. Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods

    PubMed Central

    Bransburg-Zabary, Sharron; Virozub, Alexander; Mimouni, Francis B.

    2015-01-01

    Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast. PMID:26061694

  9. Opposing plant community responses to warming with and without herbivores.

    PubMed

    Post, Eric; Pedersen, Christian

    2008-08-26

    If controls over primary productivity and plant community composition are mainly environmental, as opposed to biological, then global change may result in large-scale alterations in ecosystem structure and function. This view appears to be favored among investigations of plant biomass and community responses to experimental and observed warming. In far northern and arctic ecosystems, such studies predict increasing dominance of woody shrubs with future warming and emphasize the carbon (C)-sequestration potential and consequent atmospheric feedback potential of such responses. In contrast to previous studies, we incorporated natural herbivory by muskoxen and caribou into a 5-year experimental investigation of arctic plant community response to warming. In accordance with other studies, warming increased total community biomass by promoting growth of deciduous shrubs (dwarf birch and gray willow). However, muskoxen and caribou reduced total community biomass response, and responses of birch and willow, to warming by 19%, 46%, and 11%, respectively. Furthermore, under warming alone, the plant community shifted after 5 years away from graminoid-dominated toward dwarf birch-dominated. In contrast, where herbivores grazed, plant community composition on warmed plots did not differ from that on ambient plots after 5 years. These results highlight the potentially important and overlooked influences of vertebrate herbivores on plant community response to warming and emphasize that conservation and management of large herbivores may be an important component of mitigating ecosystem response to climate change.

  10. Situational Influences upon Children's Beliefs about Global Warming and Energy

    ERIC Educational Resources Information Center

    Devine-Wright, Patrick; Devine-Wright, Hannah; Fleming, Paul

    2004-01-01

    This paper explores children's beliefs about global warming and energy sources from a psychological perspective, focusing upon situational influences upon subjective beliefs, including perceived self-efficacy. The context of the research is one of growing concern at the potential impacts of global warming, yet demonstrably low levels of…

  11. Soil warming, carbon–nitrogen interactions, and forest carbon budgets

    PubMed Central

    Melillo, Jerry M.; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

    2011-01-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon–nitrogen interactions in atmosphere–ocean–land earth system models to accurately simulate land feedbacks to the climate system. PMID:21606374

  12. Opposing plant community responses to warming with and without herbivores

    PubMed Central

    Post, Eric; Pedersen, Christian

    2008-01-01

    If controls over primary productivity and plant community composition are mainly environmental, as opposed to biological, then global change may result in large-scale alterations in ecosystem structure and function. This view appears to be favored among investigations of plant biomass and community responses to experimental and observed warming. In far northern and arctic ecosystems, such studies predict increasing dominance of woody shrubs with future warming and emphasize the carbon (C)-sequestration potential and consequent atmospheric feedback potential of such responses. In contrast to previous studies, we incorporated natural herbivory by muskoxen and caribou into a 5-year experimental investigation of arctic plant community response to warming. In accordance with other studies, warming increased total community biomass by promoting growth of deciduous shrubs (dwarf birch and gray willow). However, muskoxen and caribou reduced total community biomass response, and responses of birch and willow, to warming by 19%, 46%, and 11%, respectively. Furthermore, under warming alone, the plant community shifted after 5 years away from graminoid-dominated toward dwarf birch-dominated. In contrast, where herbivores grazed, plant community composition on warmed plots did not differ from that on ambient plots after 5 years. These results highlight the potentially important and overlooked influences of vertebrate herbivores on plant community response to warming and emphasize that conservation and management of large herbivores may be an important component of mitigating ecosystem response to climate change. PMID:18719116

  13. Artificial warming of arctic meadow under pollution stress: Experimental design

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, notably because future warming is expected to be disproportionate as compared to world averages. Likewise, greenhouse gas (GHG) release from terrestrial ecosystems exposed to climate warming is expected to be the larg...

  14. Effects of Warm-Up Stretching Exercises on Sprint Performance

    ERIC Educational Resources Information Center

    Makaruk, Hubert; Makaruk, Beata; Kedra, Stanislaw

    2008-01-01

    Study aim: To assess direct effects of warm-up consisting of static and dynamic stretching exercises on sprint results attained by students differing in sprint performance. Material and methods: A group of 24 male and 19 female physical education students, including 12 and 9 sprinters, respectively. They performed warm-ups consisting of dynamic…

  15. Soil warming, carbon-nitrogen interactions, and forest carbon budgets.

    PubMed

    Melillo, Jerry M; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

    2011-06-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon-nitrogen interactions in atmosphere-ocean-land earth system models to accurately simulate land feedbacks to the climate system.

  16. Phenology and global warming research in Brazil

    NASA Astrophysics Data System (ADS)

    Morellato, L. P. C.

    2009-04-01

    A recent review on South American phenology research has shown an increase in phenology papers over the last two decades, especially in this new 21st century. Nevertheless, there is a lack of long term data sets or monitoring systems, or of papers addressing plant phenology and global warming. The IPCC AR4 report from 2007 has offered indisputable evidence of regional to global-scale change in seasonality, but it is supported by plant and animal phenological data from North Hemisphere and temperate species. Information from tropical regions in general and South America in particular are sparse or lacking. Here I summarize the recent outcomes of our ongoing tropical phenology research in Brazil and its potential contribution to integrate fields and understand the effects of global warming within the tropics. The Phenology Laboratory (UNESP) is located at Rio Claro, São Paulo State, Southeastern Brazil. We are looking for trends and shifts on tropical vegetation phenology, and are exploring different methods for collecting and analyzing phenology data. The phenological studies are developed in collaboration with graduate and undergraduate students, post-docs and researchers from Brazil and around the world. We established three long term monitoring programs on Southeastern Brazil from 2000 onwards: trees from an urban garden, semideciduous forest trees, and savanna cerrado woody vegetation, all based on direct weekly to monthly observation of marked plants. We have collected some discontinuous data from Atlantic rain forest trees ranging from 5 to 8 years long. I collaborate with the longest tropical wet forest phenology monitoring system in Central Amazon, and with another long term monitoring system on semi deciduous forest from South Brazil. All research programs aim, in the long run, to monitor and detect shifts on tropical plant phenology related to climatic changes. Our first preliminary findings suggest that: (i) flowering and leafing are more affected by

  17. Tracking ocean heat uptake during the surface warming hiatus

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Xie, Shang-Ping; Lu, Jian

    2016-03-01

    Ocean heat uptake is observed to penetrate deep into the Atlantic and Southern Oceans during the recent hiatus of global warming. Here we show that the deep heat penetration in these two basins is not unique to the hiatus but is characteristic of anthropogenic warming and merely reflects the depth of the mean meridional overturning circulation in the basin. We find, however, that heat redistribution in the upper 350 m between the Pacific and Indian Oceans is closely tied to the surface warming hiatus. The Indian Ocean shows an anomalous warming below 50 m during hiatus events due to an enhanced heat transport by the Indonesian throughflow in response to the intensified trade winds in the equatorial Pacific. Thus, the Pacific and Indian Oceans are the key regions to track ocean heat uptake during the surface warming hiatus.

  18. Tracking ocean heat uptake during the surface warming hiatus

    PubMed Central

    Liu, Wei; Xie, Shang-Ping; Lu, Jian

    2016-01-01

    Ocean heat uptake is observed to penetrate deep into the Atlantic and Southern Oceans during the recent hiatus of global warming. Here we show that the deep heat penetration in these two basins is not unique to the hiatus but is characteristic of anthropogenic warming and merely reflects the depth of the mean meridional overturning circulation in the basin. We find, however, that heat redistribution in the upper 350 m between the Pacific and Indian Oceans is closely tied to the surface warming hiatus. The Indian Ocean shows an anomalous warming below 50 m during hiatus events due to an enhanced heat transport by the Indonesian throughflow in response to the intensified trade winds in the equatorial Pacific. Thus, the Pacific and Indian Oceans are the key regions to track ocean heat uptake during the surface warming hiatus. PMID:27025666

  19. Recent warming at Summit, Greenland: Global context and implications

    NASA Astrophysics Data System (ADS)

    McGrath, Daniel; Colgan, William; Bayou, Nicolas; Muto, Atsuhiro; Steffen, Konrad

    2013-05-01

    at Summit, Greenland suggest that the annual mean near-surface air temperature increased at 0.09 ± 0.01°C/a over the 1982-2011 climatology period. This rate of warming, six times the global average, places Summit in the 99th percentile of all globally observed warming trends over this period. The rate of warming at Summit is increasing over time. During the instrumental period (1987-2011), warming has been greatest in the winter season, although the implications of summer warming are more acute. The annual maximum elevation of the equilibrium line and dry snow line has risen at 44 and 35 m/a over the past 15 and 18 years, respectively. Extrapolation of this observed trend now suggests, with 95% confidence intervals, that the dry snow facies of the Greenland Ice Sheet will inevitably transition to percolation facies. There is a 50% probability of this transition occurring by 2025.

  20. Tracking ocean heat uptake during the surface warming hiatus.

    PubMed

    Liu, Wei; Xie, Shang-Ping; Lu, Jian

    2016-03-30

    Ocean heat uptake is observed to penetrate deep into the Atlantic and Southern Oceans during the recent hiatus of global warming. Here we show that the deep heat penetration in these two basins is not unique to the hiatus but is characteristic of anthropogenic warming and merely reflects the depth of the mean meridional overturning circulation in the basin. We find, however, that heat redistribution in the upper 350 m between the Pacific and Indian Oceans is closely tied to the surface warming hiatus. The Indian Ocean shows an anomalous warming below 50 m during hiatus events due to an enhanced heat transport by the Indonesian throughflow in response to the intensified trade winds in the equatorial Pacific. Thus, the Pacific and Indian Oceans are the key regions to track ocean heat uptake during the surface warming hiatus.

  1. Global Warming and Neotropical Rainforests: A Historical Perspective

    NASA Astrophysics Data System (ADS)

    Jaramillo, Carlos; Cárdenas, Andrés

    2013-05-01

    There is concern over the future of the tropical rainforest (TRF) in the face of global warming. Will TRFs collapse? The fossil record can inform us about that. Our compilation of 5,998 empirical estimates of temperature over the past 120 Ma indicates that tropics have warmed as much as 7°C during both the mid-Cretaceous and the Paleogene. We analyzed the paleobotanical record of South America during the Paleogene and found that the TRF did not expand toward temperate latitudes during global warm events, even though temperatures were appropriate for doing so, suggesting that solar insolation can be a constraint on the distribution of the tropical biome. Rather, a novel biome, adapted to temperate latitudes with warm winters, developed south of the tropical zone. The TRF did not collapse during past warmings; on the contrary, its diversity increased. The increase in temperature seems to be a major driver in promoting diversity.

  2. Effects of sea surface warming on marine plankton.

    PubMed

    Lewandowska, Aleksandra M; Boyce, Daniel G; Hofmann, Matthias; Matthiessen, Birte; Sommer, Ulrich; Worm, Boris

    2014-05-01

    Ocean warming has been implicated in the observed decline of oceanic phytoplankton biomass. Some studies suggest a physical pathway of warming via stratification and nutrient flux, and others a biological effect on plankton metabolic rates; yet the relative strength and possible interaction of these mechanisms remains unknown. Here, we implement projections from a global circulation model in a mesocosm experiment to examine both mechanisms in a multi-trophic plankton community. Warming treatments had positive direct effects on phytoplankton biomass, but these were overcompensated by the negative effects of decreased nutrient flux. Zooplankton switched from phytoplankton to grazing on ciliates. These results contrast with previous experiments under nutrient-replete conditions, where warming indirectly reduced phytoplankton biomass via increased zooplankton grazing. We conclude that the effect of ocean warming on marine plankton depends on the nutrient regime, and provide a mechanistic basis for understanding global change in marine ecosystems.

  3. Warming modifies trophic cascades and eutrophication in experimental freshwater communities.

    PubMed

    Kratina, Pavel; Greig, Hamish S; Thompson, Patrick L; Carvalho-Pereira, Ticiana S A; Shurin, Jonathan B

    2012-06-01

    Climate warming is occurring in concert with other anthropogenic changes to ecosystems. However, it is unknown whether and how warming alters the importance of top-down vs. bottom-up control over community productivity and variability. We performed a 16-month factorial experimental manipulation of warming, nutrient enrichment, and predator presence in replicated freshwater pond mesocosms to test their independent and interactive impacts. Warming strengthened trophic cascades from fish to primary producers, and it decreased the impact of eutrophication on the mean and temporal variation of phytoplankton biomass. These impacts varied seasonally, with higher temperatures leading to stronger trophic cascades in winter and weaker algae blooms under eutrophication in summer. Our results suggest that higher temperatures may shift the control of primary production in freshwater ponds toward stronger top-down and weaker bottom-up effects. The dampened temporal variability of algal biomass under eutrophication at higher temperatures suggests that warming may stabilize some ecosystem processes.

  4. Tracking ocean heat uptake during the surface warming hiatus.

    PubMed

    Liu, Wei; Xie, Shang-Ping; Lu, Jian

    2016-01-01

    Ocean heat uptake is observed to penetrate deep into the Atlantic and Southern Oceans during the recent hiatus of global warming. Here we show that the deep heat penetration in these two basins is not unique to the hiatus but is characteristic of anthropogenic warming and merely reflects the depth of the mean meridional overturning circulation in the basin. We find, however, that heat redistribution in the upper 350 m between the Pacific and Indian Oceans is closely tied to the surface warming hiatus. The Indian Ocean shows an anomalous warming below 50 m during hiatus events due to an enhanced heat transport by the Indonesian throughflow in response to the intensified trade winds in the equatorial Pacific. Thus, the Pacific and Indian Oceans are the key regions to track ocean heat uptake during the surface warming hiatus. PMID:27025666

  5. Summer Drying Under Enhanced Greenhouse Gas Warming

    NASA Astrophysics Data System (ADS)

    Roesch, A.; Wild, M.; Tschuck, P.

    2005-12-01

    Present day climate and future climate projections from the latest version of the Max Planck Institute GCM, ECHAM5, at T106 resolution are used to investigate changes in the near-surface climate, focusing on summer in Europe. For the control climate, ECHAM5 has been integrated over the period 1961 to 1990, using sea surface temperature (SST) and sea ice cover (SIC) provided by the EU project PRUDENCE. Projections of future climate are based on the SRES scenario A2 from 2071-2100. SST and SIC were inferred from a coupled transient experiment carried out at the Hadley Centre with HadCM3. In summer, precipitation in the future climate integration decreases over most of continental Europe excluding Northern Scandinavia. This leads to a distinct decrease in soil moisture, with maximum absolute changes in Central Europe and Northern Spain. The highest negative signal in evaporation is found over Southern Europe where water is already limited under present-day climate conditions. This feature is closely related to the strong decrease of the water stress factor south of approximately 46N. The Bowen ratio will decline by more than 3 during the pronounced summer drying in Southern Spain, South Italy and Greece, implying a reduced evaporative cooling and thus a strong warming. In contrast, water hardly becomes a limiting factor in Central and Northern Europe in summer. The variability of summer temperatures generally increases slightly over Central Europe. Additionally, the widening of the statistical distribution exceeds 20% in major parts in Southern Europe since these areas are more often affected by summer droughts. For precipitation, the coefficient of variance (the standard deviation divided by its mean) increases by more than 100% over major parts of the Iberian Peninsula, indicating that the normalized precipitation variability significantly increases over the strongly water-limited region. In winter, ECHAM5 simulates a water-limited climate only in a minor part of

  6. Global Warming and 21st Century Drying

    NASA Technical Reports Server (NTRS)

    Cook, Benjamin I.; Smerdun, Jason E.; Seager, Richard; Coats, Sloan

    2014-01-01

    Global warming is expected to increase the frequency and intensity of droughts in the twenty-first century, but the relative contributions from changes in moisture supply (precipitation) versus evaporative demand (potential evapotranspiration; PET) have not been comprehensively assessed. Using output from a suite of general circulation model (GCM) simulations from phase 5 of the Coupled Model Intercomparison Project, projected twentyfirst century drying and wetting trends are investigated using two offline indices of surface moisture balance: the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). PDSI and SPEI projections using precipitation and Penman- Monteith based PET changes from the GCMs generally agree, showing robust cross-model drying in western North America, Central America, the Mediterranean, southern Africa, and the Amazon and robust wetting occurring in the Northern Hemisphere high latitudes and east Africa (PDSI only). The SPEI is more sensitive to PET changes than the PDSI, especially in arid regions such as the Sahara and Middle East. Regional drying and wetting patterns largely mirror the spatially heterogeneous response of precipitation in the models, although drying in the PDSI and SPEI calculations extends beyond the regions of reduced precipitation. This expansion of drying areas is attributed to globally widespread increases in PET, caused by increases in surface net radiation and the vapor pressure deficit. Increased PET not only intensifies drying in areas where precipitation is already reduced, it also drives areas into drought that would otherwise experience little drying or even wetting from precipitation trends alone. This PET amplification effect is largest in the Northern Hemisphere mid-latitudes, and is especially pronounced in western North America, Europe, and southeast China. Compared to PDSI projections using precipitation changes only, the projections incorporating both

  7. Warm Jupiters from Secular Planet–Planet Interactions

    NASA Astrophysics Data System (ADS)

    Petrovich, Cristobal; Tremaine, Scott

    2016-10-01

    Most warm Jupiters (gas-giant planets with 0.1 {{au}}≲ a≲ 1 au) have pericenter distances that are too large for significant orbital migration by tidal friction. We study the possibility that the warm Jupiters are undergoing secular eccentricity oscillations excited by an outer companion (a planet or star) in an eccentric and/or mutually inclined orbit. In this model, the warm Jupiters migrate periodically, in the high-eccentricity phase of the oscillation, but are typically observed at lower eccentricities. We show that in this model the steady-state eccentricity distribution of the warm Jupiters is approximately flat, which is consistent with the observed distribution if we restrict the sample to warm Jupiters with detected outer planetary companions. The eccentricity distribution of warm Jupiters without companions exhibits a peak at e≲ 0.2 that must be explained by a different formation mechanism. Based on a population synthesis study, we find that high-eccentricity migration excited by an outer planetary companion (1) can account for ∼ 20 % of the warm Jupiters and most of the warm Jupiters with e≳ 0.4; and (2) can produce most of the observed population of hot Jupiters, with a semimajor axis distribution that matches the observations, but fails to account adequately for ∼ 60 % of hot Jupiters with projected obliquities ≲ 20^\\circ . Thus ∼ 20 % of the warm Jupiters and ∼ 60 % of the hot Jupiters can be produced by high-eccentricity migration. We also provide predictions for the expected mutual inclinations and spin-orbit angles of the planetary systems with hot and warm Jupiters produced by high-eccentricity migration.

  8. Potential effects on health of global warming

    SciTech Connect

    Haines, A. . Whittington Hospital); Parry, M. . Environmental Change Unit)

    1993-12-01

    Prediction of the impacts of global climate change on health is complicated by a number of factors. These include: the difficulty in predicting regional changes in climate, the capacity for adaptation to climate change, the interactions between the effects of global climate change and a number of other key determinants of health, including population growth and poverty, and the availability of adequate preventive and curative facilities for diseases that may be effected by climate change. Nevertheless, it is of importance to consider the potential health impacts of global climate change for a number of reasons. It is also important to monitor diseases which could be effected by climate change in order to detect changes in incidence as early as possible and study possible interactions with other factors. It seems likely that the possible impacts on health of climate change will be a major determinant of the degree to which policies aimed at reducing global warming are followed, as perceptions of the effect of climate change to human health and well-being are particularly likely to influence public opinion. The potential health impacts of climate change can be divided into direct (primary) and indirect (secondary and tertiary) effects. Primary effects are those related to the effect of temperature on human well-being and disease. Secondary effects include the impacts on health of changes in food production, availability of water and of sea level rise. A tertiary level of impacts can also be hypothesized.

  9. Do global warming targets limit heatwave risk?

    NASA Astrophysics Data System (ADS)

    Clark, Robin T.; Murphy, James M.; Brown, Simon J.

    2010-09-01

    Climate change mitigation targets are often described in terms of annually averaged global mean temperature increases. However local interpretation of impacts resulting from these targets are required if the public is to have a sound appreciation of their consequences. Some of the largest impacts are likely to arise from changes in extreme events, for example heatwaves and floods. This article estimates future regional heat extreme changes consistent with specific global warming targets, using a new and presently unique ensemble of physically plausible climate simulations. We find that a subset of ensemble members giving globally averaged temperature increases of 2.0 ± 0.5°C shows a wide range of changes in regional temperature extremes. For example, changes in extreme single-day hot events range between 2 and 6 °C for large parts of Europe, North America and Asia for this target. Plausible variations in the model representation of forest roughness length, vegetation root depth and boundary layer cloud make the largest individual contributions to the spread of changes found in different parts of the world. However, a wide range of processes contribute to the uncertainties in the regional changes, particularly through their direct or indirect influences on the simulation of soil moisture.

  10. The Tropical Warm Pool International Cloud Experiment

    SciTech Connect

    May, Peter T.; Mather, James H.; Vaughan, Geraint; Jakob, Christian; McFarquhar, Greg; Bower, Keith; Mace, Gerald G.

    2008-05-01

    One of the most complete data sets describing tropical convection ever collected will result from the upcoming Tropical Warm Pool International Cloud Experiment (TWP-ICE) in the area around Darwin, Northern Australia in January and February 2006. The aims of the experiment, which will be operated in conjunction with the DOE Atmospheric Radiation Measurement (ARM) site in Darwin, will be to examine convective cloud systems from their initial stages through to the decay of the cirrus generated and to measure their impact on the environment. The experiment will include an unprecedented network of ground-based observations (soundings, active and passive remote sensors) combined with low, mid and high altitude aircraft for in-situ and remote sensing measurements. A crucial outcome of the experiment will be a data set suitable to provide the forcing and evaluation data required by cloud resolving and single column models as well as global climate models (GCMs) with the aim to contribute to parameterization development. This data set will provide the necessary link between the observed cloud properties and the models that are attempting to simulate them. The experiment is a large multi-agency experiment including substantial contributions from the United States DOE ARM program, ARM-UAV program, NASA, the Australian Bureau of Meteorology, CSIRO, EU programs and many universities.

  11. Ion Acoustic Modes in Warm Dense Matter

    NASA Astrophysics Data System (ADS)

    Hartley, Nicholas; Monaco, Guilio; White, Thomas; Gregori, Gianluca; Graham, Peter; Fletcher, Luke; Appel, Karen; Tschentscher, Thomas; Lee, Hae Ja; Nagler, Bob; Galtier, Eric; Granados, Eduardo; Heimann, Philip; Zastrau, Ulf; Doeppner, Tilo; Gericke, Dirk; Lepape, Sebastien; Ma, Tammy; Pak, Art; Schropp, Andreas; Glenzer, Siegfried; Hastings, Jerry

    2015-06-01

    We present results that, for the first time, show scattering from ion acoustic modes in warm dense matter, representing an unprecedented level of energy resolution in the study of dense plasmas. The experiment was carried out at the LCLS facility in California on an aluminum sample at 7 g/cc and 5 eV. Using an X-ray probe at 8 keV, shifted peaks at +/-150 meV were observed. Although the energy shifts from interactions with the acoustic waves agree with predicted values from DFT-MD models, a central (elastic) peak was also observed, which did not appear in modelled spectra and may be due to the finite timescale of the simulation. Data fitting with a hydrodynamic form has proved able to match the observed spectrum, and provide measurements of some thermodynamic properties of the system, which mostly agree with predicted values. Suggest for further experiments to determine the cause of the disparity are also given.

  12. Talking about Climate Change and Global Warming.

    PubMed

    Lineman, Maurice; Do, Yuno; Kim, Ji Yoon; Joo, Gea-Jae

    2015-01-01

    The increasing prevalence of social networks provides researchers greater opportunities to evaluate and assess changes in public opinion and public sentiment towards issues of social consequence. Using trend and sentiment analysis is one method whereby researchers can identify changes in public perception that can be used to enhance the development of a social consciousness towards a specific public interest. The following study assessed Relative search volume (RSV) patterns for global warming (GW) and Climate change (CC) to determine public knowledge and awareness of these terms. In conjunction with this, the researchers looked at the sentiment connected to these terms in social media networks. It was found that there was a relationship between the awareness of the information and the amount of publicity generated around the terminology. Furthermore, the primary driver for the increase in awareness was an increase in publicity in either a positive or a negative light. Sentiment analysis further confirmed that the primary emotive connections to the words were derived from the original context in which the word was framed. Thus having awareness or knowledge of a topic is strongly related to its public exposure in the media, and the emotional context of this relationship is dependent on the context in which the relationship was originally established. This has value in fields like conservation, law enforcement, or other fields where the practice can and often does have two very strong emotive responses based on the context of the problems being examined. PMID:26418127

  13. Sterile neutrinos as subdominant warm dark matter

    SciTech Connect

    Palazzo, A.; Cumberbatch, D.; Slosar, A.; Silk, J.

    2007-11-15

    In light of recent findings which seem to disfavor a scenario with (warm) dark matter entirely constituted of sterile neutrinos produced via the Dodelson-Widrow mechanism, we investigate the constraints attainable for this mechanism by relaxing the usual hypothesis that the relic neutrino abundance must necessarily account for all of the dark matter. We first study how to reinterpret the limits attainable from x-ray nondetection and Lyman-{alpha} forest measurements in the case that sterile neutrinos constitute only a fraction f{sub s} of the total amount of dark matter. Then, assuming that sterile neutrinos are generated in the early universe solely through the Dodelson-Widrow mechanism, we show how the x-ray and Lyman-{alpha} results jointly constrain the mass-mixing parameters governing their production. Furthermore, we show how the same data allow us to set a robust upper limit f{sub s} < or approx. 0.7 at the 2{sigma} level, rejecting the case of dominant dark matter (f{sub s}=1) at the {approx}3{sigma} level.

  14. Untangling Physical Parameters of Warm Brown Dwarfs

    NASA Astrophysics Data System (ADS)

    Cruz, Kelle L.; Douglas, Stephanie; Bdnyc

    2015-01-01

    Warm brown dwarfs offer insights into exoplanetary atmospheres because they have temperatures similar to those of hot gas giant exoplanets. However, fitting synthetic spectra to low-resolution data often produces unreasonable physical parameters (effective temperature, surface gravity, cloud parameters, etc) for brown dwarfs. Given that low- and moderate-resolution NIR data are widely available for M and L dwarfs, and that JSWT will provide moderate-resolution spectra of hot jupiters, it is important to know how well low- and medium-resolution data can constrain physical parameters given current models. We compare low- and moderate-resolution SpeX spectra (R=120-2000) for M and L dwarfs to synthetic spectra from several atmospheric models, including the Gaia-Dusty, BT-Settl, and Marley models. We employ Markov-Chain Monte Carlo (MCMC) methods to robustly fit the models to data. MCMC provides the full posterior probability distribution, illustrating any multi-modality or correlations between parameters. We present results showing how this method provides more realistic uncertainties on effective temperature, surface gravity, and cloud parameters of M and L dwarfs at low- and moderate- resolution. We also show the extent of model-to-model differences in these paramter estimates. Finally, we present an open-source code for fitting grids of synthetic spectra to data - we invite others to use it for their own studies, and we welcome conversations about and involvement in future development.

  15. Halocarbon ozone depletion and global warming potentials

    NASA Technical Reports Server (NTRS)

    Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.

    1990-01-01

    Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming).

  16. Microbial diseases of corals and global warming.

    PubMed

    Rosenberg, Eugene; Ben-Haim, Yael

    2002-06-01

    Coral bleaching and other diseases of corals have increased dramatically during the last few decades. As outbreaks of these diseases are highly correlated with increased sea-water temperature, one of the consequences of global warming will probably be mass destruction of coral reefs. The causative agent(s) of a few of these diseases have been reported: bleaching of Oculina patagonica by Vibrio shiloi; black band disease by a microbial consortium; sea-fan disease (aspergillosis) by Aspergillus sydowii; and coral white plague possibly by Sphingomonas sp. In addition, we have recently discovered that Vibrio coralyticus is the aetiological agent for bleaching the coral Pocillopora damicornis in the Red Sea. In the case of coral bleaching by V. shiloi, the major effect of increasing temperature is the expression of virulence genes by the pathogen. At high summer sea-water temperatures, V. shiloi produces an adhesin that allows it to adhere to a beta-galactoside-containing receptor in the coral mucus, penetrate into the coral epidermis, multiply intracellularly, differentiate into a viable-but-not-culturable (VBNC) state and produce toxins that inhibit photosynthesis and lyse the symbiotic zooxanthellae. In black band disease, sulphide is produced at the coral-microbial biofilm interface, which is probably responsible for tissue death. Reports of newly emerging coral diseases and the lack of epidemiological and biochemical information on the known diseases indicate that this will become a fertile area of research in the interface between microbial ecology and infectious disease.

  17. Talking about Climate Change and Global Warming.

    PubMed

    Lineman, Maurice; Do, Yuno; Kim, Ji Yoon; Joo, Gea-Jae

    2015-01-01

    The increasing prevalence of social networks provides researchers greater opportunities to evaluate and assess changes in public opinion and public sentiment towards issues of social consequence. Using trend and sentiment analysis is one method whereby researchers can identify changes in public perception that can be used to enhance the development of a social consciousness towards a specific public interest. The following study assessed Relative search volume (RSV) patterns for global warming (GW) and Climate change (CC) to determine public knowledge and awareness of these terms. In conjunction with this, the researchers looked at the sentiment connected to these terms in social media networks. It was found that there was a relationship between the awareness of the information and the amount of publicity generated around the terminology. Furthermore, the primary driver for the increase in awareness was an increase in publicity in either a positive or a negative light. Sentiment analysis further confirmed that the primary emotive connections to the words were derived from the original context in which the word was framed. Thus having awareness or knowledge of a topic is strongly related to its public exposure in the media, and the emotional context of this relationship is dependent on the context in which the relationship was originally established. This has value in fields like conservation, law enforcement, or other fields where the practice can and often does have two very strong emotive responses based on the context of the problems being examined.

  18. Global Warming: The Threat to the Planet

    NASA Astrophysics Data System (ADS)

    Hansen, James

    2007-04-01

    Paleoclimate data show that the Earth's climate is remarkably sensitive to global forcings. Positive feedbacks predominate. This allows the entire planet to be whipsawed between climate states. One feedback, the `albedo flip' property of water substance, provides a powerful trigger mechanism. A climate forcing that `flips' the albedo of a sufficient portion of an ice sheet can spark a cataclysm. Ice sheet and ocean inertia provides only moderate delay to ice sheet disintegration and a burst of added global warming. Recent greenhouse gas (GHG) emissions place the Earth perilously close to dramatic climate change that could run out of our control, with great dangers for humans and other creatures. CO2 is the largest human-made climate forcing, but CH4, O3, N2O and black carbon (BC) are important. Only intense simultaneous efforts to slow CO2 emissions and reduce non-CO2 forcings can keep climate within or near the range of the past million years. Some forcings are especially effective at high latitudes, so concerted efforts to reduce their emissions could still ``save the Arctic,'' while also having major benefits for human health, agricultural productivity, and the global environment.

  19. Responses of Antarctic Oscillation to global warming

    NASA Astrophysics Data System (ADS)

    Feng, S.

    2015-12-01

    The Antarctic Oscillation (AAO) is the major annular mode dominates the spatiotemporal variability of the atmospheric circulation in the Southern Hemisphere. This study examined the sensitivity of AAO to future warming by analyzing the outputs of 34 state-of-the-art climate models participating in phase 5 of the Coupled Model Intercomparion Project (CMIP5). The model simulations include the stabilized (RCP4.5) and business as usual (RCP8.5) scenarios as well as the idealized 1% per year increase in atmospheric CO2 to quadrupling (1pctCO2) and an instantaneous quadrupling of CO2 (abrupt4xCO2). We show that the CMIP5 models on average simulate increases in the AAO in every season by 2100 under the RCP4.5 and RCP8.5 scenarios. However, due to the impacts of ozone, aerosol and land use changes, the amplitudes of the projected changes in AAO to future climate scenarios are quit different on different seasons. After the impact of ozone, aerosol and land use changes were removed; it was found that the impact of greenhouse gases (GHGs) on AAO is similar on all seasons. The increases of AAO are accelerating following the increase of GHGs. Our results are also consistent with the simulations of 1pctCO2 and abrupt4xCO2.

  20. Mach reflection in a warm dense plasma

    SciTech Connect

    Foster, J. M.; Rosen, P. A.; Wilde, B. H.; Hartigan, P.; Perry, T. S.

    2010-11-15

    The phenomenon of irregular shock-wave reflection is of importance in high-temperature gas dynamics, astrophysics, inertial-confinement fusion, and related fields of high-energy-density science. However, most experimental studies of irregular reflection have used supersonic wind tunnels or shock tubes, and few or no data are available for Mach reflection phenomena in the plasma regime. Similarly, analytic studies have often been confined to calorically perfect gases. We report the first direct observation, and numerical modeling, of Mach stem formation for a warm, dense plasma. Two ablatively driven aluminum disks launch oppositely directed, near-spherical shock waves into a cylindrical plastic block. The interaction of these shocks results in the formation of a Mach-ring shock that is diagnosed by x-ray backlighting. The data are modeled using radiation hydrocodes developed by AWE and LANL. The experiments were carried out at the University of Rochester's Omega laser [J. M. Soures, R. L. McCrory, C. P. Verdon et al., Phys. Plasmas 3, 2108 (1996)] and were inspired by modeling [A. M. Khokhlov, P. A. Hoeflich, E. S. Oran et al., Astrophys J. 524, L107 (1999)] of core-collapse supernovae that suggest that in asymmetric supernova explosion significant mass may be ejected in a Mach-ring formation launched by bipolar jets.

  1. Talking about Climate Change and Global Warming

    PubMed Central

    Kim, Ji Yoon; Joo, Gea-Jae

    2015-01-01

    The increasing prevalence of social networks provides researchers greater opportunities to evaluate and assess changes in public opinion and public sentiment towards issues of social consequence. Using trend and sentiment analysis is one method whereby researchers can identify changes in public perception that can be used to enhance the development of a social consciousness towards a specific public interest. The following study assessed Relative search volume (RSV) patterns for global warming (GW) and Climate change (CC) to determine public knowledge and awareness of these terms. In conjunction with this, the researchers looked at the sentiment connected to these terms in social media networks. It was found that there was a relationship between the awareness of the information and the amount of publicity generated around the terminology. Furthermore, the primary driver for the increase in awareness was an increase in publicity in either a positive or a negative light. Sentiment analysis further confirmed that the primary emotive connections to the words were derived from the original context in which the word was framed. Thus having awareness or knowledge of a topic is strongly related to its public exposure in the media, and the emotional context of this relationship is dependent on the context in which the relationship was originally established. This has value in fields like conservation, law enforcement, or other fields where the practice can and often does have two very strong emotive responses based on the context of the problems being examined. PMID:26418127

  2. Proton Stopping Power in Warm Dense Hydrogen

    NASA Astrophysics Data System (ADS)

    Higginson, Drew; Chen, Sophia; Atzeni, Stefano; Gauthier, Maxence; Mangia, Feliciana; Marquès, Jean-Raphaël; Riquier, Raphaël; Fuchs, Julien

    2013-10-01

    Warm dense matter (WDM) research is fundamental to many fields of physics including fusion sciences, and astrophysical phenomena. In the WDM regime, particle stopping-power differs significantly from cold matter and ideal plasma due to free electron contributions, plasma correlation effects and electron degeneracy. The creation of WDM with temporal duration consistent with the particles probes is difficult to achieve experimentally. The short-pulse laser platform allows for the production of WDM along with relatively short bunches of protons compatible of such measurements, however, until recently, the intrinsic broadband proton spectrum was not well suited to investigate the stopping power directly. This difficulty has been overcome using a novel magnetic particle selector (ΔE/E = 10%) to select protons (in the range 100-1000 keV) as demonstrated with the ELFIE laser in LULI, France. These protons bunches probe high-density (5 × 1020 cm-3) gases (H, He) heated by a nanosecond laser to reach estimated temperatures above 100 eV. Measurement of the proton energy loss within the heated gas allows the stopping power to be determined quantitatively. The experimental results in cold matter are compared to preexisting models to give credibility to the measurement technique. The results from heated matter show that the stopping power of 450 keV protons is dramatically reduced within heated hydrogen plasma.

  3. Simulation of the December 1998 Stratospheric Major Warming

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Lahoz, W. A.; Swinbank, R.; ONeill, A.; Connew, P. M.; Zurek, R. W.

    1999-01-01

    Prior to 1991, major warmings (defined by increasing zonal mean temperatures and zonal mean easterly winds from 60degN to the pole at 10 hPa) typically occurred approximately once every two Arctic winters; a major warming in mid-Dec. 1998 was the first since Feb. 1991. The Dec. 1998 warming was also the second earliest on record. The earliest, and the only other major warming on record before the end of Dec. was in early Dec 1987; prior to that, the earliest was in late Dec./early Jan. 1984-85. The 1984-85 and 1987 warmings resulted in the warmest and weakest lower stratospheric polar vortices in the 20 years before 1998-99. Fig. 1 compares temperatures and vortex strength in 1998-99 with those in the previous 20 years, using the US National Center for Environmental Prediction (NCEP) record; 1987-88 and 1984-85 are also highlighted. The Dec. 1998 warming had a more pronounced effect on mid-stratospheric temperatures than the Dec. 1987 warming (Fig. 1a), although smaller than that of warmings later in winter (e.g., 1984-85). 10-hPa temperatures fell well below average again in late Jan. 1999 and remained unusually low until an early final warming began in late Feb. 840 K PV gradients (Fig. 1c) set a record minimum in Jan. 1999, but were near average in Feb before the final warming. The effect of the Dec. 1998 warming on lower stratospheric temperatures was comparable to that of other major warmings; there was a brief period of record-high minimum 46-hPa temperatures in early Jan 1999 (Fig. 1b), and temperatures then fell to near average for a short period in mid-Feb. Lower stratospheric PV gradients were the weakest on record during the 1998-99 winter (Fig. 1d). The evolution of the vortex and minimum temperatures during 1998-99 was remarkably similar to that during 1987-88, the only previous year when a major warming was observed before the end of Dec.

  4. Does the climate warming hiatus exist over the Tibetan Plateau?

    PubMed Central

    Duan, Anmin; Xiao, Zhixiang

    2015-01-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998–2013 (0.25 °C decade−1), compared with that during 1980–1997 (0.21 °C decade−1). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud–radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud–radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau. PMID:26329678

  5. Nonlinear regional warming with increasing CO2 concentrations

    NASA Astrophysics Data System (ADS)

    Good, Peter; Lowe, Jason A.; Andrews, Timothy; Wiltshire, Andrew; Chadwick, Robin; Ridley, Jeff K.; Menary, Matthew B.; Bouttes, Nathaelle; Dufresne, Jean Louis; Gregory, Jonathan M.; Schaller, Nathalie; Shiogama, Hideo

    2015-02-01

    When considering adaptation measures and global climate mitigation goals, stakeholders need regional-scale climate projections, including the range of plausible warming rates. To assist these stakeholders, it is important to understand whether some locations may see disproportionately high or low warming from additional forcing above targets such as 2 K (ref. ). There is a need to narrow uncertainty in this nonlinear warming, which requires understanding how climate changes as forcings increase from medium to high levels. However, quantifying and understanding regional nonlinear processes is challenging. Here we show that regional-scale warming can be strongly superlinear to successive CO2 doublings, using five different climate models. Ensemble-mean warming is superlinear over most land locations. Further, the inter-model spread tends to be amplified at higher forcing levels, as nonlinearities grow--especially when considering changes per kelvin of global warming. Regional nonlinearities in surface warming arise from nonlinearities in global-mean radiative balance, the Atlantic meridional overturning circulation, surface snow/ice cover and evapotranspiration. For robust adaptation and mitigation advice, therefore, potentially avoidable climate change (the difference between business-as-usual and mitigation scenarios) and unavoidable climate change (change under strong mitigation scenarios) may need different analysis methods.

  6. Continental warming preceding the Palaeocene-Eocene thermal maximum.

    PubMed

    Secord, Ross; Gingerich, Philip D; Lohmann, Kyger C; Macleod, Kenneth G

    2010-10-21

    Marine and continental records show an abrupt negative shift in carbon isotope values at ∼55.8 Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Palaeocene-Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to earlier warming with different origins. Yet pre-CIE warming is still uncertain. Disentangling the sequence of events before and during the CIE and PETM is important for understanding the causes of, and Earth system responses to, abrupt climate change. Here we show that continental warming of about 5 °C preceded the CIE in the Bighorn Basin, Wyoming. Our evidence, based on oxygen isotopes in mammal teeth (which reflect temperature-sensitive fractionation processes) and other proxies, reveals a marked temperature increase directly below the CIE, and again in the CIE. Pre-CIE warming is also supported by a negative amplification of δ(13)C values in soil carbonates below the CIE. Our results suggest that at least two sources of warming-the earlier of which is unlikely to have been methane-contributed to the PETM.

  7. Small inner companions of warm Jupiters: Lifetimes and legacies

    SciTech Connect

    Van Laerhoven, Christa; Greenberg, Richard

    2013-12-01

    Although warm Jupiters are generally too far from their stars for tides to be important, the presence of an inner planetary companion to a warm Jupiter can result in tidal evolution of the system. Insight into the process and its effects comes form classical secular theory of planetary perturbations. The lifetime of the inner planet may be shorter than the age of the system, because the warm Jupiter maintains its eccentricity and hence promotes tidal migration into the star. Thus a warm Jupiter observed to be alone in its system might have previously cleared away any interior planets. Before its demise, even if an inner planet is of terrestrial scale, it may promote damping of the warm Jupiter's eccentricity. Thus any inferences of the initial orbit of an observed warm Jupiter must include the possibility of a greater initial eccentricity than would be estimated by assuming it had always been alone. Tidal evolution involving multiple planets also enhances the internal heating of the planets, which readily exceeds that of stellar radiation for the inner planet, and may be great enough to affect the internal structure of warm Jupiters. Secular theory gives insight into the tidal processes, providing, among other things, a way to constrain eccentricities of transiting planets based on estimates of the tidal parameter Q.

  8. Robust cloud feedback over tropical land in a warming climate

    NASA Astrophysics Data System (ADS)

    Kamae, Youichi; Ogura, Tomoo; Watanabe, Masahiro; Xie, Shang-Ping; Ueda, Hiroaki

    2016-03-01

    Cloud-related radiative perturbations over land in a warming climate are of importance for human health, ecosystem, agriculture, and industry via solar radiation availability and local warming amplification. However, robustness and physical mechanisms responsible for the land cloud feedback were not examined sufficiently because of the limited contribution to uncertainty in global climate sensitivity. Here we show that cloud feedback in general circulation models over tropical land is robust, positive, and is relevant to atmospheric circulation change and thermodynamic constraint associated with water vapor availability. In a warming climate, spatial variations in tropospheric warming associated with climatological circulation pattern result in a general weakening of tropical circulation and a dynamic reduction of land cloud during summer monsoon season. Limited increase in availability of water vapor also reduces the land cloud. The reduction of land cloud depends on global-scale oceanic warming and is not sensitive to regional warming patterns. The robust positive feedback can contribute to the warming amplification and drying over tropical land in the future.

  9. Experimental warming effects on the bacterial community structure and diversity

    NASA Astrophysics Data System (ADS)

    Kim, W.; Han, S.; Adams, J.; Son, Y.

    2014-12-01

    The objective of this study is to investigate the responses of soil bacterial community to future temperature increase by conducting open-field warming experiment. We conducted an open-field experimental warming system using infra-red heater in 2011 and regulated the temperature of warmed plots by 3oC higher than that of control plots constantly. The seeds of Pinus densiflora, Abies holophylla, Abies koreana, Betula costata, Quercus variabilis, Fraxinus rhynchophylla, and Zelkova serrata were planted in each 1 m × 1 m plot (n=3) in April, 2012. We collected soil samples from the rhizosphere of 7 tree species. DNA was extracted and PCR-amplified for the bacterial 16S gene targeting V1-V3 region. The paired-end sequencing was performed at Beijing Genome Institute (BGI, Hong Kong, China) using 2× 100 bp Hiseq2000 (Illumina). This study aimed to answer the following prediction/hypothesis: 1) Experimental warming will change the structure of soil bacterial community, 2) There will be distinct 'indicator group' which response to warming treatment relatively more sensitive than other groups. 3) Warming treatment will enhance the microbial activity in terms of soil respiration. 4) The rhizoplane bacterial communities for each of 7 tree species will show different response pattern to warming treatment. Since the sequence data does not arrive before the submission deadline, therefore, we would like to present the results and discussions on December 2014, AGU Fall Meeting.

  10. Does the climate warming hiatus exist over the Tibetan Plateau?

    PubMed

    Duan, Anmin; Xiao, Zhixiang

    2015-01-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998-2013 (0.25 °C decade(-1)), compared with that during 1980-1997 (0.21 °C decade(-1)). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud-radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud-radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau. PMID:26329678

  11. Respiratory function during warm-up exercise in athletes.

    PubMed

    Kesavachandran, C; Shashidhar, S

    1997-04-01

    The theme of the present study is to stress the importance of duration of warm-up exercise on respiratory functions in athletes. Significant improvements in athletic performance was achieved due to warm-up exercise owing to increase in blood flow, muscle and core temperature. The optimum intensity and duration are required to bring about the desired warm-up. A close examination on respiratory functions and its relationship with exercise has not been studied extensively. The present investigation is to explore the various respiratory functions in relation to the intensity and duration in preadolescent athletes before and after warm-up exercise. The results show a significant increase in vital capacity after 25 min and a significant reduction in FEV0.5, FEF75% and FEF25-75% after 45 min of warm-up exercise. The results suggest that a warm-up exercise of short duration (25 min) and mild intensity was beneficial than long duration (45 min) and intense exercise. Although the performance of athletes was not directly measured during exercise, these data demonstrate the benefit of warm-up.

  12. Tropospheric circulation during the early twentieth century Arctic warming

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-06-01

    The early twentieth century Arctic warming (ETCAW) between 1920 and 1940 is an exceptional feature of climate variability in the last century. Its warming rate was only recently matched by recent warming in the region. Unlike recent warming largely attributable to anthropogenic radiative forcing, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi-member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analyzing sensible heat flux components and regional differences, climate models are not able to reproduce the heat flux evolution found in reanalysis and reconstruction datasets. These datasets show an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis reveals the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it is suggested that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  13. Changes in Extreme Warm and Cold Temperatures Associated with 20th Century Global Warming

    NASA Astrophysics Data System (ADS)

    Sardeshmukh, P. D.; Compo, G. P.; McColl, C.; Penland, C.

    2015-12-01

    Has 20thcentury global warming resulted in increases of extreme warm temperatures and decreases of extreme cold temperatures around the globe? One would certainly expect this to be so if the changes in the extreme temperature probabilities were determined only by the mean shift and not by changes in the width and/or shape of the temperature distribution. In reality, however, the latter two effects could also be important. Even ignoring changes of shape, it is easily shown that a 25% reduction of standard deviation, for example, can completely offset the effect of a mean positive shift of 0.5 standardized units on the probabilities of extreme positive values. A 25% increase of standard deviation can similarly offset the effect of the mean shift on the probabilities of extreme negative values. It is possible for such changes of standard deviation to occur in regions of large circulation and storminess changes associated with global warming. With this caveat in mind, we have investigated the change in probability of extreme weekly-averaged near-surface air temperatures, in both winter and summer, from the first half-century (1901-1950) to the last half-century (1960-2009) of the 1901 to 2009 period. We have done this using two newly available global atmospheric datasets (ERA-20C and 20CR-v2c) and large ensembles of global coupled climate model simulations of this period, plus very large ensembles of uncoupled atmospheric model simulations of our own. The results are revealing. In the tropics, the changes in the extreme warm and cold temperature probabilities are indeed generally consistent with those expected from the mean shift of the distribution. Outside the tropics, however, they are generally significantly inconsistent with the mean temperature shift, with many regions showing little or no change in the positive temperature extremes and in some instances even a decrease. In such regions, it is clear that the change in the temperature standard deviation is

  14. Establishing native warm season grasses on Eastern Kentucky strip mines

    SciTech Connect

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

    1998-12-31

    The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat.

  15. A Warm South Pole? Yes, on Neptune!

    NASA Astrophysics Data System (ADS)

    2007-09-01

    Summer season on Neptune creates escape route for methane An international team of astronomers using ESO's Very Large Telescope has discovered that the south pole of Neptune is much hotter than the rest of the planet. This is consistent with the fact that it is late southern summer and this region has been in sunlight for about 40 years. ESO PR Photo 41/07 ESO PR Photo 41/07 Neptune's 'Hot' South Pole (VISIR/VLT) The scientists are publishing the first temperature maps of the lowest portion of Neptune's atmosphere, showing that this warm south pole is providing an avenue for methane to escape out of the deep atmosphere. "The temperatures are so high that methane gas, which should be frozen out in the upper part of Neptune's atmosphere (the stratosphere), can leak out through this region," said Glenn Orton, lead author of the paper reporting the results. "This solves a long-standing problem of identifying the source of Neptune's high stratospheric methane abundances." The temperature at the south pole is higher than anywhere else on the planet by about 10 degrees Celsius. The average temperature on Neptune is about minus 200 degrees Celsius. Neptune, the farthest planet of our solar system, is located about 30 times farther away from the Sun than Earth is. Only about 1/900th as much sunlight reaches Neptune as our planet. Yet, the small amount of sunlight it receives significantly affects the planet's atmosphere. The astronomers found that these temperature variations are consistent with seasonal changes. A Neptunian year lasts about 165 Earth years. It has been summer in the south pole of Neptune for about 40 years now, and they predict that as winter turns to summer in the north pole, an abundance of methane will leak out of a warm north pole in about 80 years. "Neptune's south pole is currently tilted toward the Sun, just like the Earth's south pole is tilted toward the Sun during summer in the Southern Hemisphere," explains Orton. "But on Neptune the antarctic

  16. Sneutrino warm inflation in the minimal supersymmetric model

    SciTech Connect

    Bastero-Gil, Mar; Berera, Arjun

    2005-11-15

    The model of RH neutrino fields coupled to the MSSM is shown to yield a large parameter regime of warm inflation. In the strong dissipative regime, it is shown that inflation, driven by a single sneutrino field, occurs with all field amplitudes below the Planck scale. Analysis is also made of leptogenesis, neutrino mass generation and gravitino constraints. A new warm inflation scenario is purposed in which one scalar field drives a period of warm inflation and a second field drives a subsequent phase of reheating. Such a model is able to reduce the final temperature after inflation, thus helping to mitigate gravitino constraints.

  17. The dynamics of the warming hiatus over the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Huang, Jianping; Xie, Yongkun; Guan, Xiaodan; Li, Dongdong; Ji, Fei

    2016-05-01

    A warming hiatus is a period of relatively little change in global mean surface air temperatures (SAT). Many studies have attributed the current warming hiatus to internal climate variability (ICV). But there is less work on discussion of the dynamics about how these ICV modes influence cooling over land in the Northern Hemisphere (NH). Here we demonstrate the warming hiatus was more significant over the continental NH. We explored the dynamics of the warming hiatus from a global perspective and investigated the mechanisms of the reversing from accelerated warming to hiatus, and how ICV modes influence SAT change throughout the NH land. It was found that these ICV modes and Arctic amplification can excite a decadal modulated oscillation (DMO), which enhances or suppresses the long-term trend on decadal to multi-decadal timescales. When the DMO is in an upward (warming) phase, it contributes to an accelerated warming trend, as in last 20 years of twentieth-century. It appears that there is a downward swing in the DMO occurring at present, which has balanced or reduced the radiative forced warming and resulted in the recent global warming hiatus. The DMO modulates the SAT, in particular, the SAT of boreal cold months, through changes in the asymmetric meridional and zonal thermal forcing (MTF and ZTF). The MTF represents the meridional temperature gradients between the mid- and high-latitudes, and the ZTF represents the asymmetry in temperatures between the extratropical large-scale warm and cold zones in the zonal direction. Via the different performance of combined MTF and ZTF, we found that the DMO's modulation effect on SAT was strongest when both weaker (stronger) MTF and stronger (weaker) ZTF occurred simultaneously. And the current hiatus is a result of a downward DMO combined with a weaker MTF and stronger ZTF, which stimulate both a weaker polar vortex and westerly winds, along with the amplified planetary waves, thereby facilitating southward invasion of

  18. Global Warming in the 21st Century: An Alternate Scenario

    NASA Technical Reports Server (NTRS)

    Hansen, James E.

    2000-01-01

    Evidence on a broad range of time scales, from Proterozoic to the most recent periods, shows that the Earth's climate responds sensitively to global forcings. In the past few decades the Earth's surface has warmed rapidly, apparently in response to increasing anthropogenic greenhouse gases in the atmosphere. The conventional view is that the current global warming rate will continue or accelerate in the 21st century. I will describe an alternate scenario that would slow the rate of global warming and reduce the danger of dramatic climate change. But reliable prediction of future climate change requires improved knowledge of the carbon cycle and global observations that allow interpretation of ongoing climate change.

  19. Global genetic change tracks global climate warming in Drosophila subobscura.

    PubMed

    Balanyá, Joan; Oller, Josep M; Huey, Raymond B; Gilchrist, George W; Serra, Luis

    2006-09-22

    Comparisons of recent with historical samples of chromosome inversion frequencies provide opportunities to determine whether genetic change is tracking climate change in natural populations. We determined the magnitude and direction of shifts over time (24 years between samples on average) in chromosome inversion frequencies and in ambient temperature for populations of the fly Drosophila subobscura on three continents. In 22 of 26 populations, climates warmed over the intervals, and genotypes characteristic of low latitudes (warm climates) increased in frequency in 21 of those 22 populations. Thus, genetic change in this fly is tracking climate warming and is doing so globally.

  20. HS 1603+3820 and its Warm Absorber

    NASA Astrophysics Data System (ADS)

    Nikołajuk, M.; Różańska, A.; Czerny, B.; Dobrzycki, A.

    2009-07-01

    We use photoionization codes CLOUDY and TITAN to obtain physical conditions in the absorbing medium close to the nucleus of a distant quasar (z = 2.54) HS 1603+3820. We found that the total column density of this Warm Absorber is 2 x 1022 cm-2. Due to the softness of the quasars spectrum the modelling allowed us also to determine uniquely the volume hydrogen density of this warm gas (n = 1010 cm-3) which combined with the other quasar parameters leads to a distance determination to the Warm Absorber from the central source which is ~ 1.5 x 1016 cm.

  1. Heat waves and warm periods in Slovakia

    NASA Astrophysics Data System (ADS)

    Faško, Pavel; Bochníček, Oliver; Markovič, Ladislav; Švec, Marek

    2016-04-01

    The scenarios of climate change caused by human activity show that frequency of occurrence and extent of heat waves in the interior of Europe is increasing. Among the most exposed regions in this regard should the area of southeastern and eastern Austria and south-western Slovakia. The relatively faster increase in the number of heat waves in this area is related also to potential desertification in this region just east of the Alps, since during summer, weather fronts advancing from the west are consequently losing their original features and moderating influence. Summer weather patterns for this area should in the future more closely remind climate typical for some inland areas of southwestern, southern and southeastern Europe. A certain shift of climate zones from south to north should thus modify future climate and Slovakia. Despite the complex natural conditions the existing trends derived from results of meteorological measurements and observations are clear and they confirm warming of climate in this region. Observations and measurements in the recent years of the 21st century confirm, that heat waves are no longer rare phenomenon during summer, but are systematically appearing even in colder regions of northern Slovakia. What is very remarkable and will be necessary to pay more attention to, is the fact that these heat waves are expanding into previously unaffected areas, associated with the lack of rainfall and drought, on larger regional scale. In this study heat wave periods and individual heat events and days are statistically identified in the time series characteristics of air temperature at selected meteorological stations for the period from the mid-20th century until 2015, in case of available historical data even for longer period.

  2. Accessibility Dynamics in a Warming Arctic

    NASA Astrophysics Data System (ADS)

    Stephenson, S.; Smith, L. C.; Agnew, J. A.

    2010-12-01

    A promising area of future research is the intersection of the physical manifestations of climate change with the human response. We present a first modeling framework integrating the changing accessibility regimes of the Arctic maritime and terrestrial environments. Climate change has spurred global interest in the Arctic as an arena of new potential for petroleum exploration and intercontinental shipping. While General Circulation Models predict thickness and extent of sea ice throughout the 21st century, the degree to which ice thinning and recession will increase transportation access at the circumpolar scale is not well understood. At the same time, warming of the Arctic terrestrial environment foreshadows a shorter winter road operating season and reduced access for communities and industries reliant on these temporary roads for winter ground transport. CCSM3 temperature data and CSIM5 sea ice data for two periods of analysis (2000-2014; 2045-2059) were integrated with GLC2000 land cover, ETOPO2 elevation and slope, VMAP0 infrastructure, and other terrain feature datasets to calculate circumpolar accessibility for a baseline and a future scenario. Accessibility data were combined in a GIS to produce maps of changing transportation access on land and at sea by mid-century. For the period 2045-2059, access at sea was found to increase substantially throughout the Arctic for ships with some icebreaking capability: previously inaccessible thick ice cover decreased in the central Arctic Ocean by an average of 64% annually. Conversely, terrestrial access by winter roads was found to decrease markedly in November and April while access along inland waterways increased in October. As climate change brings warmer temperatures to some of the world’s remotest communities, the remoteness of communities itself undergoes a profound change. This study attempts to provide a physical basis to the discussion of human activity in the Arctic over the next 50 years.

  3. Arctic Warming, Greenland Melt and Moulins

    NASA Astrophysics Data System (ADS)

    Steffen, K.; Huff, R.; Behar, A.

    2007-12-01

    Air temperatures on the Greenland ice sheet have increased by 4 deg. C since 1991. The ice sheet melt area increased by 30% for the western part between 1979-2006, with record melt years in 1987, 1991, 1998, 2002, 2005, and possibly the most extreme melt year in 2007. The increasing trend in the total area of melting bare ice is unmistakable at 13% per year, significant at a probability of 0.99. Hence, the bare ice region, the wet snow region, and the equilibrium line altitude have moved further inland and resulting in increased melt water flux towards the coast. Warm and extended air temperatures are to blame for 1.5 m water equivalent surface reduction at the long-term equilibrium line altitude, 1100 m elevation at 70 deg. N during summer 2007. Increase in ice velocity in the ablation region and the concurrent increase in melt water suggests that water penetrates to great depth through moulins and cracks, lubricating the bottom of the ice sheet. New insight was gained of subsurface hydrologic channels and cavities using new instrumentation and a video system during the melt peak in August 2007. Volume and geometry of a 100 m deep moulin were mapped with a rotating laser, and photographs with digital cameras. Sub-glacial hydrologic channels were investigated and filmed using a tethered, autonomous system, several hundred meters into the ice. These new results will be discussed in view of the rapid increase in melt area and mass loss of the Greenland ice sheet due to increasing air temperatures.

  4. Global Warming Estimation From Microwave Sounding Unit

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Dalu, G.

    1998-01-01

    Microwave Sounding Unit (MSU) Ch 2 data sets, collected from sequential, polar-orbiting, Sun-synchronous National Oceanic and Atmospheric Administration operational satellites, contain systematic calibration errors that are coupled to the diurnal temperature cycle over the globe. Since these coupled errors in MSU data differ between successive satellites, it is necessary to make compensatory adjustments to these multisatellite data sets in order to determine long-term global temperature change. With the aid of the observations during overlapping periods of successive satellites, we can determine such adjustments and use them to account for the coupled errors in the long-term time series of MSU Ch 2 global temperature. In turn, these adjusted MSU Ch 2 data sets can be used to yield global temperature trend. In a pioneering study, Spencer and Christy (SC) (1990) developed a procedure to derive the global temperature trend from MSU Ch 2 data. Such a procedure can leave unaccounted residual errors in the time series of the temperature anomalies deduced by SC, which could lead to a spurious long-term temperature trend derived from their analysis. In the present study, we have developed a method that avoids the shortcomings of the SC procedure, the magnitude of the coupled errors is not determined explicitly. Furthermore, based on some assumptions, these coupled errors are eliminated in three separate steps. Such a procedure can leave unaccounted residual errors in the time series of the temperature anomalies deduced by SC, which could lead to a spurious long-term temperature trend derived from their analysis. In the present study, we have developed a method that avoids the shortcomings of the SC procedures. Based on our analysis, we find there is a global warming of 0.23+/-0.12 K between 1980 and 1991. Also, in this study, the time series of global temperature anomalies constructed by removing the global mean annual temperature cycle compares favorably with a similar

  5. Experiments of water formation on warm silicates

    SciTech Connect

    He, Jiao; Vidali, Gianfranco

    2014-06-10

    When dust grains have a higher temperature than they would have in dense clouds, and when H, H{sub 2}, and O{sub 2} have a negligible residence time on grains, the formation of water should still be possible via the hydrogenation of OH and Eley-Rideal-type reactions. We determined that the OH desorption energy from an amorphous silicate surface is at least 143 meV (1656 K). This is 400 K higher than the value previously used in chemical models of the interstellar medium and is possibly as high as 410 meV (4760 K). This extends the temperature range for the efficient formation of water on grains from about 30 K to at least 50 K, and possibly over 100 K. We do not find evidence that water molecules leave the surface upon formation. Instead, through a thermal programmed desorption experiment, we find that water formed on the surface of an amorphous silicate desorbs at around 160 K. We also measured the cross-sections for the reaction of H and D with an O{sub 3} layer on an amorphous silicate surface at 50 K. The values of the cross-sections, σ{sub H} = 1.6 ± 0.27 Å{sup 2} and σ{sub D} = 0.94 ± 0.09 Å{sup 2}, respectively, are smaller than the size of an O{sub 3} molecule, suggesting the reaction mechanism is more likely Eley-Rideal than hot-atom. Information obtained through these experiments should help theorists evaluate the relative contribution of water formation on warm grains versus in the gas phase.

  6. The properties of warm dark matter haloes

    NASA Astrophysics Data System (ADS)

    Lovell, Mark R.; Frenk, Carlos S.; Eke, Vincent R.; Jenkins, Adrian; Gao, Liang; Theuns, Tom

    2014-03-01

    Well-motivated elementary particle candidates for the dark matter, such as the sterile neutrino, behave as warm dark matter (WDM). For particle masses of the order of a keV, free streaming produces a cutoff in the linear fluctuation power spectrum at a scale corresponding to dwarf galaxies. We investigate the abundance and structure of WDM haloes and subhaloes on these scales using high resolution cosmological N-body simulations of galactic haloes of mass similar to the Milky Way's. On scales larger than the free-streaming cutoff, the initial conditions have the same power spectrum and phases as one of the cold dark matter (CDM) haloes previously simulated by Springel et al. as part of the Virgo consortium Aquarius project. We have simulated four haloes with WDM particle masses in the range 1.5-2.3 keV and, for one case, we have carried out further simulations at varying resolution. N-body simulations in which the power spectrum cutoff is resolved are known to undergo artificial fragmentation in filaments producing spurious clumps which, for small masses (<107 M⊙ in our case) outnumber genuine haloes. We have developed a robust algorithm to identify these spurious objects and remove them from our halo catalogues. We find that the WDM subhalo mass function is suppressed by well over an order magnitude relative to the CDM case for masses <109 M⊙. Requiring that there should be at least as many subhaloes as there are observed satellites in the Milky Way leads to a conservative lower limit to the (thermal equivalent) WDM particle mass of ˜ 1.5 keV. WDM haloes and subhaloes have cuspy density distributions that are well described by Navarro-Frenk-White or Einasto profiles. Their central densities are lower for lower WDM particle masses and none of the models we have considered suffering from the `too big to fail' problem recently highlighted by Boylan-Kolchin et al.

  7. Polar bears in a warming climate.

    PubMed

    Derocher, Andrew E; Lunn, Nicholas J; Stirling, Ian

    2004-04-01

    Polar bears (Ursus maritimus) live throughout the ice-covered waters of the circumpolar Arctic, particularly in near shore annual ice over the continental shelf where biological productivity is highest. However, to a large degree under scenarios predicted by climate change models, these preferred sea ice habitats will be substantially altered. Spatial and temporal sea ice changes will lead to shifts in trophic interactions involving polar bears through reduced availability and abundance of their main prey: seals. In the short term, climatic warming may improve bear and seal habitats in higher latitudes over continental shelves if currently thick multiyear ice is replaced by annual ice with more leads, making it more suitable for seals. A cascade of impacts beginning with reduced sea ice will be manifested in reduced adipose stores leading to lowered reproductive rates because females will have less fat to invest in cubs during the winter fast. Non-pregnant bears may have to fast on land or offshore on the remaining multiyear ice through progressively longer periods of open water while they await freeze-up and a return to hunting seals. As sea ice thins, and becomes more fractured and labile, it is likely to move more in response to winds and currents so that polar bears will need to walk or swim more and thus use greater amounts of energy to maintain contact with the remaining preferred habitats. The effects of climate change are likely to show large geographic, temporal and even individual differences and be highly variable, making it difficult to develop adequate monitoring and research programs. All ursids show behavioural plasticity but given the rapid pace of ecological change in the Arctic, the long generation time, and the highly specialised nature of polar bears, it is unlikely that polar bears will survive as a species if the sea ice disappears completely as has been predicted by some. PMID:21680496

  8. Polar bears in a warming climate.

    PubMed

    Derocher, Andrew E; Lunn, Nicholas J; Stirling, Ian

    2004-04-01

    Polar bears (Ursus maritimus) live throughout the ice-covered waters of the circumpolar Arctic, particularly in near shore annual ice over the continental shelf where biological productivity is highest. However, to a large degree under scenarios predicted by climate change models, these preferred sea ice habitats will be substantially altered. Spatial and temporal sea ice changes will lead to shifts in trophic interactions involving polar bears through reduced availability and abundance of their main prey: seals. In the short term, climatic warming may improve bear and seal habitats in higher latitudes over continental shelves if currently thick multiyear ice is replaced by annual ice with more leads, making it more suitable for seals. A cascade of impacts beginning with reduced sea ice will be manifested in reduced adipose stores leading to lowered reproductive rates because females will have less fat to invest in cubs during the winter fast. Non-pregnant bears may have to fast on land or offshore on the remaining multiyear ice through progressively longer periods of open water while they await freeze-up and a return to hunting seals. As sea ice thins, and becomes more fractured and labile, it is likely to move more in response to winds and currents so that polar bears will need to walk or swim more and thus use greater amounts of energy to maintain contact with the remaining preferred habitats. The effects of climate change are likely to show large geographic, temporal and even individual differences and be highly variable, making it difficult to develop adequate monitoring and research programs. All ursids show behavioural plasticity but given the rapid pace of ecological change in the Arctic, the long generation time, and the highly specialised nature of polar bears, it is unlikely that polar bears will survive as a species if the sea ice disappears completely as has been predicted by some.

  9. Comparing new-technology passive warming versus traditional passive warming methods for optimizing perioperative body core temperature.

    PubMed

    Bender, Miriam; Self, Beverly; Schroeder, Ellen; Giap, Brandon

    2015-08-01

    Hypothermia puts surgical patients at risk for adverse outcomes. Traditional passive warming methods are mostly ineffective in reducing hypothermia. New-technology passive warming holds promise as an effective method for promoting and sustaining normothermia throughout surgery. The purpose of this retrospective cohort study was to compare the effectiveness of new-technology passive warming with traditional methods. We measured core body temperature at anesthesia induction and at the end of surgery for patients undergoing robotic-assisted prostatectomy/hysterectomy in the lithotomy position who received either new-technology passive warming (n = 30) or traditional linens and gel pads (n = 35). The traditionally warmed cohort had no change in temperature (35.9° C ± 0.6° C presurgery vs 35.9° C ± 0.7° C postsurgery; t = 0.47; P = .66). The intervention cohort showed a significant increase in temperature (35.75° C ± 0.52° C presurgery vs 36.30° C ± 0.53° C postsurgery; t = 4.64; P < .001). A repeated-measure analysis of variance adjusting for surgery duration and fluid administration confirmed the significance (F = 17.254; P < .001), suggesting that new-technology passive warming may effectively complement active warming to reduce perioperative hypothermia.

  10. Simulation of early 20th century global warming

    PubMed

    Delworth; Knutson

    2000-03-24

    The observed global warming of the past century occurred primarily in two distinct 20-year periods, from 1925 to 1944 and from 1978 to the present. Although the latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear because this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) forcing. Results from a set of six integrations of a coupled ocean-atmosphere climate model suggest that the warming of the early 20th century could have resulted from a combination of human-induced radiative forcing and an unusually large realization of internal multidecadal variability of the coupled ocean-atmosphere system. This conclusion is dependent on the model's climate sensitivity, internal variability, and the specification of the time-varying human-induced radiative forcing.

  11. Earth's Long-Term Warming Trend, 1880-2015

    NASA Video Gallery

    This visualization illustrates Earth’s long-term warming trend, showing temperature changes from 1880 to 2015 as a rolling five-year average. Orange colors represent temperatures that are warmer th...

  12. The Climate Policy Narrative for a Dangerously Warming World

    SciTech Connect

    Sanford, Todd; Frumhoff, Peter; Luers, Amy; Gulledge, Jay

    2014-01-01

    It is time to acknowledge that global average temperatures will likely rise above the 2 C policy target and consider how that deeply troubling prospect should affect priorities for communicating and managing the risks of a dangerously warming climate.

  13. A global warming forum: Scientific, economic, and legal overview

    SciTech Connect

    Geyer, R.A.

    1993-01-01

    A Global Warming Forum covers in detail five general subject areas aimed at providing first, the scientific background and technical information available on global warming and second, a study and evaluation of the role of economic, legal, and political considerations in global warming. The five general topic areas discussed are the following: (1) The role of geophysical and geoengineering methods to solve problems related to global climatic change; (2) the role of oceanographic and geochemical methods to provide evidence for global climatic change; (3) the global assessment of greenhouse gas production including the need for additional information; (4) natural resource management needed to provide long-term global energy and agricultural uses; (5) legal, policy, and educational considerations required to properly evaluate global warming proposals.

  14. Meridional heat transport at the onset of winter stratospheric warming

    NASA Technical Reports Server (NTRS)

    Conte, M.

    1981-01-01

    A continuous vertical flow of energy toward high altitude was verified. This process produced a dynamic instability of the stratospheric polar vortex. A meridional heat transport ws primed toward the north, which generated a warming trend.

  15. Optimal Detection of Global Warming using Temperature Profiles

    NASA Technical Reports Server (NTRS)

    Leroy, Stephen S.

    1997-01-01

    Optimal fingerprinting is applied to estimate the amount of time it would take to detect warming by increased concentrations of carbon dioxide in monthly averages of temperature profiles over the Indian Ocean.

  16. The Warm-Blooded Plant of the Swamps.

    ERIC Educational Resources Information Center

    Camazine, Scott

    1986-01-01

    Describes remarkable characteristics of the skunk cabbage (Symplocarpus foetidus) which make it an interesting swamp plant to study in February and March: its warm-blooded nature, unpleasant skunky odor, and peculiar root system. (NEC)

  17. Warming and Resource Availability Shift Food Web Structure and Metabolism

    PubMed Central

    O'Connor, Mary I.; Piehler, Michael F.; Leech, Dina M.; Anton, Andrea; Bruno, John F.

    2009-01-01

    Climate change disrupts ecological systems in many ways. Many documented responses depend on species' life histories, contributing to the view that climate change effects are important but difficult to characterize generally. However, systematic variation in metabolic effects of temperature across trophic levels suggests that warming may lead to predictable shifts in food web structure and productivity. We experimentally tested the effects of warming on food web structure and productivity under two resource supply scenarios. Consistent with predictions based on universal metabolic responses to temperature, we found that warming strengthened consumer control of primary production when resources were augmented. Warming shifted food web structure and reduced total biomass despite increases in primary productivity in a marine food web. In contrast, at lower resource levels, food web production was constrained at all temperatures. These results demonstrate that small temperature changes could dramatically shift food web dynamics and provide a general, species-independent mechanism for ecological response to environmental temperature change. PMID:19707271

  18. Evaluating Arctic warming mechanisms in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Franzke, Christian L. E.; Lee, Sukyoung; Feldstein, Steven B.

    2016-07-01

    Arctic warming is one of the most striking signals of global warming. The Arctic is one of the fastest warming regions on Earth and constitutes, thus, a good test bed to evaluate the ability of climate models to reproduce the physics and dynamics involved in Arctic warming. Different physical and dynamical mechanisms have been proposed to explain Arctic amplification. These mechanisms include the surface albedo feedback and poleward sensible and latent heat transport processes. During the winter season when Arctic amplification is most pronounced, the first mechanism relies on an enhancement in upward surface heat flux, while the second mechanism does not. In these mechanisms, it has been proposed that downward infrared radiation (IR) plays a role to a varying degree. Here, we show that the current generation of CMIP5 climate models all reproduce Arctic warming and there are high pattern correlations—typically greater than 0.9—between the surface air temperature (SAT) trend and the downward IR trend. However, we find that there are two groups of CMIP5 models: one with small pattern correlations between the Arctic SAT trend and the surface vertical heat flux trend (Group 1), and the other with large correlations (Group 2) between the same two variables. The Group 1 models exhibit higher pattern correlations between Arctic SAT and 500 hPa geopotential height trends, than do the Group 2 models. These findings suggest that Arctic warming in Group 1 models is more closely related to changes in the large-scale atmospheric circulation, whereas in Group 2, the albedo feedback effect plays a more important role. Interestingly, while Group 1 models have a warm or weak bias in their Arctic SAT, Group 2 models show large cold biases. This stark difference in model bias leads us to hypothesize that for a given model, the dominant Arctic warming mechanism and trend may be dependent on the bias of the model mean state.

  19. Electron-ion temperature equilibration in warm dense tantalum

    SciTech Connect

    Doppner, T; LePape, S.; Ma, T.; Pak, A.; Hartley, N. J.; Peters, L.; Gregori, G.; Belancourt, P.; Drake, R. P.; Chapman, D. A.; Richardson, S.; Gericke, D. O.; Glenzer, S. H.; Khaghani, D.; Neumayer, P.; Vorberger, J.; White, T. G.

    2014-11-05

    We present measurements of electron-ion temperature equilibration in proton-heated tantalum, under warm dense matter conditions. Our results agree with theoretical predictions for metals calculated using input data from ab initio simulations. Furthermore, the fast relaxation observed in the experiment contrasts with much longer equilibration times found in proton heated carbon, indicating that the energy flow pathways in warm dense matter are far from being fully understood.

  20. Measurement of electron-ion relaxation in warm dense copper

    DOE PAGESBeta

    Cho, B. I.; Ogitsu, T.; Engelhorn, K.; Correa, A. A.; Ping, Y.; Lee, J. W.; Bae, L. J.; Prendergast, D.; Falcone, R. W.; Heimann, P. A.

    2016-01-06

    Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. As a result, data are compared with various theoretical models.

  1. Anthropogenic Warming Has Increased Drought Risk In California

    NASA Astrophysics Data System (ADS)

    Diffenbaugh, N. S.; Swain, D. L.; Touma, D. E.

    2015-12-01

    California is currently in the midst of a record-setting drought. The drought began in 2012 and now includes the lowest calendar-year and 12-mo precipitation, the highest annual temperature, and the most extreme drought indicators on record. The extremely warm and dry conditions have led to acute water shortages, groundwater overdraft, critically low streamflow, and enhanced wildfire risk. Analyzing historical climate observations from California, we find that precipitation deficits in California were more than twice as likely to yield drought years if they occurred when conditions were warm. We find that although there has not been a substantial change in the probability of either negative or moderately negative precipitation anomalies in recent decades, the occurrence of drought years has been greater in the past two decades than in the preceding century. In addition, the probability that precipitation deficits co-occur with warm conditions and the probability that precipitation deficits produce drought have both increased. Climate model experiments with and without anthropogenic forcings reveal that human activities have increased the probability that dry precipitation years are also warm. Further, a large ensemble of climate model realizations reveals that additional global warming over the next few decades is very likely to create ˜100% probability that any annual-scale dry period is also extremely warm. We therefore conclude that anthropogenic warming is increasing the probability of co-occurring warm-dry conditions like those that have created the acute human and ecosystem impacts associated with the "exceptional" 2012-2014 drought in California.

  2. Unabated global surface temperature warming: evaluating the evidence

    NASA Astrophysics Data System (ADS)

    Karl, T. R.; Arguez, A.

    2015-12-01

    New insights related to time-dependent bias corrections in global surface temperatures have led to higher rates of warming over the past few decades than previously reported in the IPCC Fifth Assessment Report (2014). Record high global temperatures in the past few years have also contributed to larger trends. The combination of these factors and new analyses of the rate of temperature change show unabated global warming since at least the mid-Twentieth Century. New time-dependent bias corrections account for: (1) differences in temperatures measured from ships and drifting buoys; (2) improved corrections to ship measured temperatures; and (3) the larger rates of warming in polar regions (particularly the Arctic). Since 1951, the period over which IPCC (2014) attributes over half of the observed global warming to human causes, it is shown that there has been a remarkably robust and sustained warming, punctuated with inter-annual and decadal variability. This finding is confirmed through simple trend analysis and Empirical Mode Decomposition (EMD). Trend analysis however, especially for decadal trends, is sensitive to selection bias of beginning and ending dates. EMD has no selection bias. Additionally, it can highlight both short- and long-term processes affecting the global temperature times series since it addresses both non-linear and non-stationary processes. For the new NOAA global temperature data set, our analyses do not support the notion of a hiatus or slowing of long-term global warming. However, sub-decadal periods of little (or no warming) and rapid warming can also be found, clearly showing the impact of inter-annual and decadal variability that previously has been attributed to both natural and human-induced non-greenhouse forcings.

  3. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. PMID:27152990

  4. Control optimization of the cryoplant warm compressor station for EAST

    SciTech Connect

    Zhuang, M.; Hu, L. B.; Zhou, Z. W.; Xia, G. H.

    2014-01-29

    The cryogenic control system for EAST (Experimental Advanced Superconducting Tokamak) was designed based on DeltaV DCS of Emerson Corporation. The automatic control of the cryoplant warm compressors has been implemented. However, with ever-degrading performance of critical equipment, the cryoplant operation in the partial design conditions makes the control system fluctuate and unstable. In this paper, the warm compressor control system was optimized to eliminate the pressure oscillation based on the expert PID theory.

  5. Warming and drought reduce temperature sensitivity of nitrogen transformations.

    PubMed

    Novem Auyeung, Dolaporn S; Suseela, Vidya; Dukes, Jeffrey S

    2013-02-01

    Shifts in nitrogen (N) mineralization and nitrification rates due to global changes can influence nutrient availability, which can affect terrestrial productivity and climate change feedbacks. While many single-factor studies have examined the effects of environmental changes on N mineralization and nitrification, few have examined these effects in a multifactor context or recorded how these effects vary seasonally. In an old-field ecosystem in Massachusetts, USA, we investigated the combined effects of four levels of warming (up to 4 °C) and three levels of precipitation (drought, ambient, and wet) on net N mineralization, net nitrification, and potential nitrification. We also examined the treatment effects on the temperature sensitivity of net N mineralization and net nitrification and on the ratio of C mineralization to net N mineralization. During winter, freeze-thaw events, snow depth, and soil freezing depth explained little of the variation in net nitrification and N mineralization rates among treatments. During two years of treatments, warming and altered precipitation rarely influenced the rates of N cycling, and there was no evidence of a seasonal pattern in the responses. In contrast, warming and drought dramatically decreased the apparent Q10 of net N mineralization and net nitrification, and the warming-induced decrease in apparent Q10 was more pronounced in ambient and wet treatments than the drought treatment. The ratio of C mineralization to net N mineralization varied over time and was sensitive to the interactive effects of warming and altered precipitation. Although many studies have found that warming tends to accelerate N cycling, our results suggest that warming can have little to no effect on N cycling in some ecosystems. Thus, ecosystem models that assume that warming will consistently increase N mineralization rates and inputs of plant-available N may overestimate the increase in terrestrial productivity and the magnitude of an important

  6. Warming and drought reduce temperature sensitivity of nitrogen transformations.

    PubMed

    Novem Auyeung, Dolaporn S; Suseela, Vidya; Dukes, Jeffrey S

    2013-02-01

    Shifts in nitrogen (N) mineralization and nitrification rates due to global changes can influence nutrient availability, which can affect terrestrial productivity and climate change feedbacks. While many single-factor studies have examined the effects of environmental changes on N mineralization and nitrification, few have examined these effects in a multifactor context or recorded how these effects vary seasonally. In an old-field ecosystem in Massachusetts, USA, we investigated the combined effects of four levels of warming (up to 4 °C) and three levels of precipitation (drought, ambient, and wet) on net N mineralization, net nitrification, and potential nitrification. We also examined the treatment effects on the temperature sensitivity of net N mineralization and net nitrification and on the ratio of C mineralization to net N mineralization. During winter, freeze-thaw events, snow depth, and soil freezing depth explained little of the variation in net nitrification and N mineralization rates among treatments. During two years of treatments, warming and altered precipitation rarely influenced the rates of N cycling, and there was no evidence of a seasonal pattern in the responses. In contrast, warming and drought dramatically decreased the apparent Q10 of net N mineralization and net nitrification, and the warming-induced decrease in apparent Q10 was more pronounced in ambient and wet treatments than the drought treatment. The ratio of C mineralization to net N mineralization varied over time and was sensitive to the interactive effects of warming and altered precipitation. Although many studies have found that warming tends to accelerate N cycling, our results suggest that warming can have little to no effect on N cycling in some ecosystems. Thus, ecosystem models that assume that warming will consistently increase N mineralization rates and inputs of plant-available N may overestimate the increase in terrestrial productivity and the magnitude of an important

  7. Measurement of Electron-Ion Relaxation in Warm Dense Copper

    NASA Astrophysics Data System (ADS)

    Cho, B. I.; Ogitsu, T.; Engelhorn, K.; Correa, A. A.; Ping, Y.; Lee, J. W.; Bae, L. J.; Prendergast, D.; Falcone, R. W.; Heimann, P. A.

    2016-01-01

    Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. Data are compared with various theoretical models.

  8. Global Warming and Energy Transition: A Public Policy Imperative

    NASA Astrophysics Data System (ADS)

    Stone, G. T.

    2006-12-01

    The historic transition from fossil fuels to alternative energy resources has begun. This development is commonly attributed to increasing energy costs and the need for energy security. Looming ever larger, however, is the issue that will soon drive the third energy revolution: global warming. A preponderance of evidence documents accelerating warming, enlarging impacts, and human causes -- principally combustion of fossil fuels. The carbon dioxide (C02) content of Earth's atmosphere has increased more than 35 percent since the beginning of the industrial revolution and is the highest in 650,000 years. This dramatic rise of C02 and attendant positive feedbacks are already forcing significant impacts worldwide. These include atmospheric warming with shifting climatic and habitat zones, spreading tropical disease, and more extreme weather events; rapid ice loss at high latitude and high altitude; ocean warming and acidification with coral reef bleaching and intensifying tropical storms; rising sea level; and accelerating extinction rates. The 2007 draft report of the Intergovernmental Panel on Climate Change (IPCC) predicts greater warming than in previous models. A tipping point to abrupt climate change may be imminent. It is incumbent upon geoscientists and geoscience educators to assume leadership in addressing this challenge through public outreach and general education. The following topics should be integrated into all appropriate courses: the evidence of global warming and its causes; observed present and predicted future impacts of global warming; mitigation and adaptation strategies; and implications for energy policies and economic opportunities. New entry-level science and general education courses -- such as Climate Change Fundamentals and Energy in Nature, Technology, and Society -- are proving to be effective should be widely developed In addition, by workshops and presentations to civic and business organizations and by demonstrated examples of

  9. Electron-ion temperature equilibration in warm dense tantalum

    DOE PAGESBeta

    Doppner, T; LePape, S.; Ma, T.; Pak, A.; Hartley, N. J.; Peters, L.; Gregori, G.; Belancourt, P.; Drake, R. P.; Chapman, D. A.; et al

    2014-11-05

    We present measurements of electron-ion temperature equilibration in proton-heated tantalum, under warm dense matter conditions. Our results agree with theoretical predictions for metals calculated using input data from ab initio simulations. Furthermore, the fast relaxation observed in the experiment contrasts with much longer equilibration times found in proton heated carbon, indicating that the energy flow pathways in warm dense matter are far from being fully understood.

  10. Measurement of Electron-Ion Relaxation in Warm Dense Copper

    PubMed Central

    Cho, B. I.; Ogitsu, T.; Engelhorn, K.; Correa, A. A.; Ping, Y.; Lee, J. W.; Bae, L. J.; Prendergast, D.; Falcone, R. W.; Heimann, P. A.

    2016-01-01

    Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. Data are compared with various theoretical models. PMID:26733236

  11. Anthropogenic warming has increased drought risk in California.

    PubMed

    Diffenbaugh, Noah S; Swain, Daniel L; Touma, Danielle

    2015-03-31

    California is currently in the midst of a record-setting drought. The drought began in 2012 and now includes the lowest calendar-year and 12-mo precipitation, the highest annual temperature, and the most extreme drought indicators on record. The extremely warm and dry conditions have led to acute water shortages, groundwater overdraft, critically low streamflow, and enhanced wildfire risk. Analyzing historical climate observations from California, we find that precipitation deficits in California were more than twice as likely to yield drought years if they occurred when conditions were warm. We find that although there has not been a substantial change in the probability of either negative or moderately negative precipitation anomalies in recent decades, the occurrence of drought years has been greater in the past two decades than in the preceding century. In addition, the probability that precipitation deficits co-occur with warm conditions and the probability that precipitation deficits produce drought have both increased. Climate model experiments with and without anthropogenic forcings reveal that human activities have increased the probability that dry precipitation years are also warm. Further, a large ensemble of climate model realizations reveals that additional global warming over the next few decades is very likely to create ∼ 100% probability that any annual-scale dry period is also extremely warm. We therefore conclude that anthropogenic warming is increasing the probability of co-occurring warm-dry conditions like those that have created the acute human and ecosystem impacts associated with the "exceptional" 2012-2014 drought in California.

  12. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered.

  13. Anthropogenic warming has increased drought risk in California.

    PubMed

    Diffenbaugh, Noah S; Swain, Daniel L; Touma, Danielle

    2015-03-31

    California is currently in the midst of a record-setting drought. The drought began in 2012 and now includes the lowest calendar-year and 12-mo precipitation, the highest annual temperature, and the most extreme drought indicators on record. The extremely warm and dry conditions have led to acute water shortages, groundwater overdraft, critically low streamflow, and enhanced wildfire risk. Analyzing historical climate observations from California, we find that precipitation deficits in California were more than twice as likely to yield drought years if they occurred when conditions were warm. We find that although there has not been a substantial change in the probability of either negative or moderately negative precipitation anomalies in recent decades, the occurrence of drought years has been greater in the past two decades than in the preceding century. In addition, the probability that precipitation deficits co-occur with warm conditions and the probability that precipitation deficits produce drought have both increased. Climate model experiments with and without anthropogenic forcings reveal that human activities have increased the probability that dry precipitation years are also warm. Further, a large ensemble of climate model realizations reveals that additional global warming over the next few decades is very likely to create ∼ 100% probability that any annual-scale dry period is also extremely warm. We therefore conclude that anthropogenic warming is increasing the probability of co-occurring warm-dry conditions like those that have created the acute human and ecosystem impacts associated with the "exceptional" 2012-2014 drought in California. PMID:25733875

  14. Legacy Effects of Warming on Permafrost Carbon Release

    NASA Astrophysics Data System (ADS)

    Blok, D.; Faucherre, S.; Banyasz, I.; Michelsen, A.; Elberling, B.

    2015-12-01

    Warming in arctic tundra may thaw currently frozen upper permafrost layers, potentially releasing organic carbon (C) that was preserved by cold conditions for hundreds or thousands of years. Apart from the direct control of temperature on permafrost carbon dioxide (CO2) production, warming may alter permafrost CO2 production rates through changes in either permafrost C quality or changes in microbial communities. We incubated exogenous permafrost cores in four different warming experiments in NE-Greenland. The experiments were located in both Salix- and Cassiope-dominated sub-sites and were established in 2004 (old site) and 2007 (new site). Permafrost cores were buried as "open incubators" (free vertical water flow) at both 5-10cm depth (shallow) and 15-20cm depth (deep) in both non-manipulated (control) and warmed plots (warmed) and incubated for 2 years in the field. After retrieval from the field, permafrost cores were kept undisturbed in a lab fridge for three months, after which sub-samples were incubated at 5°C in glass vials. Permafrost CO2 production rates were subsequently measured after one week, four weeks and three months incubation in the lab. We measured the legacy effects of in situ conditions, including experimental warming in the field, on permafrost respiration under controlled laboratory conditions. We assessed the effects of plot type, vegetation type, experiment age, and incubation depth on permafrost CO2 production rates. After 3 months incubation in the lab, we measured a positive effect of warming on permafrost CO2 production rates for shallow-incubated cores, but not for deep-incubated cores. Production rates of CO2 were significantly higher for cores incubated in the old site compared to the new site. Our results suggest that warming may not only directly stimulate permafrost C release, but also indirectly through the effects of infiltrating water, nutrients and microbes from near-surface soil layers.

  15. Expansion of World Drylands Under Global Warming

    NASA Astrophysics Data System (ADS)

    Feng, S.; Fu, Q.; Hu, Q. S.

    2012-12-01

    The world drylands including both semi-arid and arid regions comprise of one-third of the global land surfaces, which support 14% of the world's inhabitants and a significant share of the world agriculture. Because of meager annual precipitation and large potential evaporative water loss, the ecosystems over drylands are fragile and sensitive to the global change. By analyzing the observations during 1948-2008 and 20 fully coupled climate model simulations from CMIP5 for the period 1900-2100, this study evaluated the changes of the world drylands that are defined with a modified form of the Thornthwaite's moisture index. The results based on observational data showed that the world drylands are steadily expanding during the past 60 years. The areas occupied by drylands in 1994-2008 is about 2.0×10^6km^2 (or 4%) larger than the average during the 1950s. Such an expansion is also a robust feature in the simulations of the 20 global climate models, though the rate is much smaller in the models. A stronger expanding rate is projected during the first half of this century than the simulations in the last century, followed by accelerating expansion after 2050s under the high greenhouse gas emission scenario (RCP8.5). By the end of this century, the world drylands are projected to be over 58×10^6km^2 (or 11% increase compared to the 1961-1990 climatology). The projected expansion of drylands, however, is not homogeneous over the world drylands, with major expansion of arid regions over the southwest North America, the northern fringe of Africa, southern Africa and Australia. Major expansions of semi-arid regions are projected over the north side of the Mediterranean, southern Africa, North and South America. The global warming is the main factor causing the increase of potential evapotranspiration estimated by Penman-Monteith algorithm, which in turn dominants the expansion of drylands. The widening of Hadley cell, which has impact on both temperature and precipitation

  16. Warm World Ocean Thermohaline Circulation Model

    NASA Astrophysics Data System (ADS)

    Zimov, N.; Zimov, S. A.

    2014-12-01

    Modern day ocean circulation is dominated by thermal convection with cold waters subsiding in the Northern Atlantic, filling the ocean interior with cold and heavy water. However, ocean circulation diminished during the last glaciation and consequently the downwelling of the cold. Therefore interior ocean water temperatures must have been affected by other mechanisms which are negligible in the current state. We propose that the submergence of highly saline water from warm seas with high rates of evaporation (like the Red or Mediterranean Sea) was a major factor controlling ocean circulation during the last glaciation. Even today, waters in these poorly connected seas are the heaviest waters in the World ocean (1.029 g/cm3). The second mechanism affecting ocean temperature is the geothermal heat flux. With no heat exchange between the atmosphere and the ocean, geothermal heat flux through the ocean floor is capable of increasing ocean temperature by tens of degrees C over a 100 thousand year glacial cycle. To support these hypotheses we present an ocean box model that describes thermohaline circulation in the World Ocean. According to the model parameters, all water circulation is driven by the water density gradient. Boxes include high-latitude seas, high salinity seas, surface ocean, glaciers, and rift and lateral zones of the ocean interior. External heat sources are radiative forcing, affected by Milankovich cycles, and geothermal heat flux. Additionally this model accounts for the heat produced by organic rain decay. Taking all input parameters close to currently observed values, the model manages to recreate the glacial-interglacial cycles. During the glacial periods only haline circulation takes place, the ocean is strongly stratified, and the interior ocean accumulates heat while high-latitudes accumulate ice. 112,000 years after glaciation starts, water density on the ocean bottom becomes equal to the density of water in high-latitude seas, strong thermal

  17. Mixtures in the Warm, Dense Matter Regine

    NASA Astrophysics Data System (ADS)

    Collins, Lee A.

    2009-03-01

    The bulk of normal matter from planets to the intergalactic medium exists as a composite of various elemental constituents. The interactions among these different species determine the basic properties of such diverse environments. For dilute systems, simple gas laws serve well to describe the mixing. However, once the density and temperature increase, more sophisticated treatments of the electronic component and dynamics become necessary. For the warm, dense matter (WDM) region [10^22-10^25 atoms/cm^3 and 300K - 10^6 K], quantum Monte Carlo and molecular dynamics, utilizing finite-temperature density functional theory (DFT), have served as the basic exploratory tools and benchmarks for other methods. The computational intensity of both methods, especially for mixtures, which require large sample sizes to attain statistical accuracy, has focused considerable attention on mixing prescriptions based on the properties of the pure atomic constituents. Though extensively utilized in many disciplines, these rules have received very little verification [1,2]. We examine the validity of two such rules, density and pressure mixing, for several systems and concentrations by comparing against quantum calculations for the fully-interacting composite. We find considerable differences in some regimes, especially for optical properties. We also probe dynamical properties such as diffusion and viscosity as well as the role of impurities. Finally, as a means of extending DFT results to higher temperature regimes, we also study orbital-free molecular dynamics (OFMD) approaches [3] based on various approximations to the basic density functional. These OFMD schemes permit a smooth transition from the WDM region to simpler one-component plasma and ideal gas models. Research in collaboration with J.D. Kress (LANL), D.A. Horner (LANL), and Flavien Lambert (CEA). [4pt] [1] D.A. Horner, J.D. Kress, and L.A. Collins, Phys. Rev. B 77, 064102 (2008).[0pt] [2] F. Lambert et. al. Phys. Rev. E

  18. Global warming, energy use, and economic growth

    NASA Astrophysics Data System (ADS)

    Khanna, Neha

    The dissertation comprises four papers that explore the interactions between global warming, energy use, and economic growth. While the papers are separate entities, they share the underlying theme of highlighting national differences in the growth experience and their implications for long-term energy use and climate change. The first paper provides an overview of some key economic issues in the climate change literature. In doing so, the paper critically appraises the 1995 draft report of Working Group III of the Intergovernmental Panel on Climate Change. The focus is the choice of a pure rate of time preference in the economic modeling of climate change, abatement costs differentials between developed and developing countries, and contrasting implications of standard discount rates and value of life estimates for these two country groups. The second paper develops a global model that takes account of the depletion of oil resources in the context of a geo-economic model for climate change. It is found that in the presence of non-decreasing carbon and energy intensities and declining petroleum availability, the carbon emissions trajectory is much higher than that typically projected by other models of this genre. Furthermore, by introducing price and income sensitive demand functions for fossil fuels, the model provides a framework to assess the effectiveness of fuel specific carbon taxes in reducing the COsb2 emissions trajectory. Cross-price substitution effects necessitate unrealistically high tax rates in order to lower the projected emissions trajectory to the optimal level. The economic structure of five integrated assessment models for climate change is reviewed in the third paper, with a special focus on the macroeconomic and damage assessment modules. The final paper undertakes an econometric estimation of the changing shares of capital, labour, energy, and technical change in explaining the growth patterns of 38 countries. Production elasticities vary by

  19. Stronger warming effects on microbial abundances in colder regions

    PubMed Central

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-01-01

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra, and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our findings therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions. PMID:26658882

  20. Stronger warming effects on microbial abundances in colder regions

    SciTech Connect

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra, and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our results therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.

  1. Indirect aerosol effect increases CMIP5 models projected Arctic warming

    DOE PAGESBeta

    Chylek, Petr; Vogelsang, Timothy J.; Klett, James D.; Hengartner, Nicholas; Higdon, Dave; Lesins, Glen; Dubey, Manvendra K.

    2016-02-20

    Phase 5 of the Coupled Model Intercomparison Project (CMIP5) climate models’ projections of the 2014–2100 Arctic warming under radiative forcing from representative concentration pathway 4.5 (RCP4.5) vary from 0.9° to 6.7°C. Climate models with or without a full indirect aerosol effect are both equally successful in reproducing the observed (1900–2014) Arctic warming and its trends. However, the 2014–2100 Arctic warming and the warming trends projected by models that include a full indirect aerosol effect (denoted here as AA models) are significantly higher (mean projected Arctic warming is about 1.5°C higher) than those projected by models without a full indirect aerosolmore » effect (denoted here as NAA models). The suggestion is that, within models including full indirect aerosol effects, those projecting stronger future changes are not necessarily distinguishable historically because any stronger past warming may have been partially offset by stronger historical aerosol cooling. In conclusion, the CMIP5 models that include a full indirect aerosol effect follow an inverse radiative forcing to equilibrium climate sensitivity relationship, while models without it do not.« less

  2. Permafrost degradation stimulates carbon loss from experimentally warmed tundra.

    PubMed

    Natali, Susan M; Schuur, Edward A G; Webb, Elizabeth E; Pries, Caitlin E Hicks; Crummer, Kathryn G

    2014-03-01

    A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years because cold and waterlogged conditions have protected soil organic material from microbial decomposition. As the climate warms this vast and frozen C pool is at risk of being thawed, decomposed, and released to the atmosphere as greenhouse gasses. At the same time, some C losses may be offset by warming-mediated increases in plant productivity. Plant and microbial responses to warming ultimately determine net C exchange from ecosystems, but the timing and magnitude of these responses remain uncertain. Here we show that experimental warming and permafrost (ground that remains below 0 degrees C for two or more consecutive years) degradation led to a two-fold increase in net ecosystem C uptake during the growing season. However, warming also enhanced winter respiration, which entirely offset growing-season C gains. Winter C losses may be even higher in response to actual climate warming than to our experimental manipulations, and, in that scenario, could be expected to more than double overall net C losses from tundra to the atmosphere. Our results highlight the importance of winter processes in determining whether tundra acts as a C source or sink, and demonstrate the potential magnitude of C release from the permafrost zone that might be expected in a warmer climate.

  3. How warm was Greenland during the last interglacial period?

    NASA Astrophysics Data System (ADS)

    Landais, Amaelle; Masson-Delmotte, Valérie; Capron, Emilie; Langenbroeck, Petra; Bakker, Pepijn; Stone, Emma; Fischer, Hubertus; Vinther, Bo; Dahl-Jensen, Dorthe

    2016-04-01

    The last interglacial period (LIG, ~129-116 thousand years ago) provides the most recent evidence for the response of Greenland and Antarctic ice sheets to polar warming above pre-industrial level, and a valuable test bed for ice sheet models. Key constraints on past changes in both ice sheet topography and surface temperature are derived from Greenland ice cores. The large warming estimated from the recent NEEM ice core drilled in northwest Greenland (8 ±4°C above pre-industrial) together with the evidence for limited local ice thinning have led to the "NEEM paradox", suggesting more stability of the ice sheet than simulated by ice flow models in response to such large warming. Here, we provide a new assessment of the LIG warming using ice core air isotopic composition (d15N) together with available relationships for Greenland between accumulation rate and temperature. The temperature at the upstream NEEM deposition site is estimated to be between -20°C to -24°C which is consistent with the 8±4°C warming relative to pre-industrial previously determined from water isotopic records measured on the NEEM ice, although we feel the lower end of this range to be more likely. Moreover, we show that under such warm temperature, melting of snow probably led to a significant firn shrinking by 15 m. We show that confirmation of this high temperature range for the LIG in Greenland is difficult to reconcile with climate modeling experiments

  4. Rationale for Implementation of Warm Cardiac Surgery in Pediatrics

    PubMed Central

    Durandy, Yves

    2016-01-01

    Cardiac surgery was developed thanks to the introduction of hypothermia and cardiopulmonary bypass in the early 1950s. The deep hypothermia protective effect has been essential to circulatory arrest complex cases repair. During the early times of open-heart surgery, a major concern was to decrease mortality and to improve short-term outcomes. Both mortality and morbidity dramatically decreased over a few decades. As a consequence, the drawbacks of deep hypothermia, with or without circulatory arrest, became more and more apparent. The limitation of hypothermia was particularly evident for the brain and regional perfusion was introduced as a response to this problem. Despite a gain in popularity, the results of regional perfusion were not fully convincing. In the 1990s, warm surgery was introduced in adults and proved to be safe and reliable. This option eliminates the deleterious effect of ischemia–reperfusion injuries through a continuous, systemic coronary perfusion with warm oxygenated blood. Intermittent warm blood cardioplegia was introduced later, with impressive results. We were convinced by the easiness, safety, and efficiency of warm surgery and shifted to warm pediatric surgery in a two-step program. This article outlines the limitations of hypothermic protection and the basic reasons that led us to implement pediatric warm surgery. After tens of thousands of cases performed across several centers, this reproducible technique proved a valuable alternative to hypothermic surgery. PMID:27200324

  5. The effect of global warming on infectious diseases.

    PubMed

    Kurane, Ichiro

    2010-12-01

    Global warming has various effects on human health. The main indirect effects are on infectious diseases. Although the effects on infectious diseases will be detected worldwide, the degree and types of the effect are different, depending on the location of the respective countries and socioeconomical situations. Among infectious diseases, water- and foodborne infectious diseases and vector-borne infectious diseases are two main categories that are forecasted to be most affected. The effect on vector-borne infectious diseases such as malaria and dengue fever is mainly because of the expansion of the infested areas of vector mosquitoes and increase in the number and feeding activity of infected mosquitoes. There will be increase in the number of cases with water- and foodborne diarrhoeal diseases. Even with the strongest mitigation procedures, global warming cannot be avoided for decades. Therefore, implementation of adaptation measures to the effect of global warming is the most practical action we can take. It is generally accepted that the impacts of global warming on infectious diseases have not been apparent at this point yet in East Asia. However, these impacts will appear in one form or another if global warming continues to progress in future. Further research on the impacts of global warming on infectious diseases and on future prospects should be conducted.

  6. Stronger warming effects on microbial abundances in colder regions

    DOE PAGESBeta

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra,more » and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our results therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.« less

  7. Echinococcus granulosus: in vitro effectiveness of warm water on protoscolices.

    PubMed

    Moazeni, Mohammad; Alipour-Chaharmahali, Mohammad-Reza

    2011-01-01

    Hydatid disease is one of the most important helminthic diseases worldwide. Hydatid cysts may be found anywhere in the body. The most effective treatment of hydatid cyst is surgical operation. Spillage of live protoscolices during the operation is the major cause of recurrence. Instillation of scolicidal agent into hydatid cyst is the most commonly employed measure to prevent this complication. To date, many scolicidal agents have been used for inactivation of the hydatid cyst content, however, most common scolicidal agents may cause unacceptable side-effects, limiting their use. In this study the scolicidal effect of warm water (45, 50, 55, and 60 °C) at different exposure times (1, 2, 3, 4, 5, 6, 8, 10, 12, and 15 min) is investigated. Protoscolices were collected aseptically from sheep livers containing hydatid cyst. Viability of protoscolices was determined by 0.1% eosin staining. Even though the highest scolicidal activity of warm water at 45 °C was 40.4% at the end of 15 min, the best scolicidal effect (100%) of warm water at 50, 55, and 60 °C was obtained after 5, 2, and 1 min, respectively. The results of this in vitro study showed that warm water at 50-60 °C can be regarded as an effective scolicidal agent. Warm water is commonly available, easily prepared, and inexpensive. In vivo scolicidal activity of warm water and also the possible side effects need further investigation.

  8. Diminished Response of Arctic Plants to Warming over Time

    PubMed Central

    Kremers, Kelseyann S.; Hollister, Robert D.; Oberbauer, Steven F.

    2015-01-01

    The goal of this study is to determine if the response of arctic plants to warming is consistent across species, locations and time. This study examined the impact of experimental warming and natural temperature variation on plants at Barrow and Atqasuk, Alaska beginning in 1994. We considered observations of plant performance collected from 1994–2000 “short-term” and those from 2007–2012 “long-term”. The plant traits reported are the number of inflorescences, inflorescence height, leaf length, and day of flower emergence. These traits can inform us about larger scale processes such as plant reproductive effort, plant growth, and plant phenology, and therefore provide valuable insight into community dynamics, carbon uptake, and trophic interactions. We categorized traits of all species monitored at each site into temperature response types. We then compared response types across traits, plant growth forms, sites, and over time to analyze the consistency of plant response to warming. Graminoids were the most responsive to warming and showed a positive response to temperature, while shrubs were generally the least responsive. Almost half (49%) of response types (across all traits, species, and sites combined) changed from short-term to long-term. The percent of plants responsive to warming decreased from 57% (short-term) to 46% (long-term). These results indicate that the response of plants to warming varies over time and has diminished overall in recent years. PMID:25767881

  9. Tropospheric circulation during the early twentieth century Arctic warming

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-04-01

    The early twentieth century Arctic warming (ETCAW) between 1920-1940 is an exceptional feature of climate dynamics in the last century and its warming rate was only recently matched by anthropogenic global warming amplification in the Arctic region. However, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We use these gridded datasets to investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analysing heat flux components and regional differences, it was found that climate models are not able to reproduce the heat flux evolution shown by reanalysis and reconstruction datasets. These datasets compute an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis revealed the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it could be shown that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  10. Alpine proglacial suspended sediment dynamics in warm and cool ablation seasons: Implications for global warming

    NASA Astrophysics Data System (ADS)

    Stott, Tim; Mount, Nick

    2007-01-01

    SummaryData on suspended sediment dynamics and loads obtained from the Torrent du Glacier Noir, Ecrins Massif, SE France, during the unusually warm 2003 and cooler 2004 ablation seasons are used to indicate the likely future impacts of climate warming on suspended sediment transport processes in temperate Alpine proglacial zones. Suspended sediment concentration (SSC) and discharge ( Q) were continuously monitored for 16-day periods during July 2003 and July 2004. SSC was monitored by automated pump sampling during diurnal events in each season and supplemented by a 10 min turbidity record. Q was monitored at a range of flows and a rating curve used to convert a 10 min water level record into Q. Air temperature (AT) was also logged at 10 min intervals throughout the study. Comparison of the 2003 and 2004 monitoring periods showed that daily mean AT measured at the site was 1.2 °C higher in 2003, mean Q was 2.3 times higher, and the suspended sediment load (SSL) was between 3.1 and 4.1 times greater in July 2003 than for the same period in the 2004 ablation season. There is an increase in SSC during the 2004 observation period which is less apparent in 2003, most likely because higher ATs and consequently higher Q earlier in the 2003 melt season had removed available sediment before the study took place in July. The rating curve method for estimating SSL produced a total load for the 16-day study period in 2003 which, when corrected upwards to account for statistical bias, was 10 314 ± 743 t or 95% of the load estimated from the turbidity record for the same period. In 2004 the corrected SSC- Q rating curve estimate was 2504 ± 126 t while the estimate from the turbidity record was 743 ± 112 t though a more sensitive turbidity sensor produced a higher estimate of 3474 ± 302 t. While the different SSL estimation methods in 2004 are not in perfect agreement, the contrast between the two seasons is nevertheless very clear, and is largely attributed to a mean

  11. Direct Imaging of Warm Extrasolar Planets

    SciTech Connect

    Macintosh, B

    2005-04-11

    One of the most exciting scientific discoveries in the last decade of the twentieth century was the first detection of planets orbiting a star other than our own. By now more than 130 extrasolar planets have been discovered indirectly, by observing the gravitational effects of the planet on the radial velocity of its parent star. This technique has fundamental limitations: it is most sensitive to planets close to their star, and it determines only a planet's orbital period and a lower limit on the planet's mass. As a result, all the planetary systems found so far are very different from our own--they have giant Jupiter-sized planets orbiting close to their star, where the terrestrial planets are found in our solar system. Such systems have overturned the conventional paradigm of planet formation, but have no room in them for habitable Earth-like planets. A powerful complement to radial velocity detections of extrasolar planets will be direct imaging--seeing photons from the planet itself. Such a detection would allow photometric measurements to determine the temperature and radius of a planet. Also, direct detection is most sensitive to planets in wide orbits, and hence more capable of seeing solar systems resembling our own, since a giant planet in a wide orbit does not preclude the presence of an Earth-like planet closer to the star. Direct detection, however, is extremely challenging. Jupiter is roughly a billion times fainter than our sun. Two techniques allowed us to overcome this formidable contrast and attempt to see giant planets directly. The first is adaptive optics (AO) which allows giant earth-based telescopes, such as the 10 meter W.M. Keck telescope, to partially overcome the blurring effects of atmospheric turbulence. The second is looking for young planets: by searching in the infrared for companions to young stars, we can see thermal emission from planets that are still warm with the heat of their formation. Together with a UCLA team that leads the

  12. Atmospheric General Circulation Changes under Global Warming

    NASA Astrophysics Data System (ADS)

    Palipane, Erool

    The work in this thesis is mainly two-fold. First we study the internal variability of the general circulation and focus our study on the annular modes and how important it is to simulate the subsynoptic scales in the circulation. In the next major section we will try to understand the mechanisms of the forced response and the mechanisms leading towards the jet shift from transient evolution in Atmospheric general circulation models. In the first part, in an attempt to assess the benefit of resolving the sub-synoptic to mesoscale processes, the spatial and temporal characteristics of the Annular Modes (AMs), in particular those related to the troposphere-stratosphere interaction, are evaluated for moderate- and high-horizontal resolution simulations with a global atmospheric general circulation model (AGCM), in comparison with the ERA40 re- analysis. Relative to the CMIP-type climate models, the IFS AGCM demonstrates notable improvement in capturing the key characteristics of the AMs. Notably, the performance with the high horizontal resolution version of the model is systematically superior to the moderate resolution on all metrics examined, including the variance of the AMs at different seasons of the year, the intrinsic e-folding time scales of the AMs, and the downward influence from the stratosphere to troposphere in the AMs. Moreover, the high-resolution simulation with a greater persistence in the intrinsic variability of the SAM projects an appreciably larger shift of the surface westerly wind during the Southern Hemisphere summer under climate change. In the second part, the response of the atmospheric circulation to greenhouse gas-induced SST warming is investigated using large ensemble experiments with two AGCMs, with a focus on the robust feature of the poleward shift of the eddy driven jet. In these experiments, large ensembles of simulations are conducted by abruptly switching the SST forcing on from January 1st to focus on the wintertime circulation

  13. Global crop yield losses from recent warming

    SciTech Connect

    Lobell, D; Field, C

    2006-06-02

    Global yields of the world-s six most widely grown crops--wheat, rice, maize, soybeans, barley, sorghum--have increased since 1961. Year-to-year variations in growing season minimum temperature, maximum temperature, and precipitation explain 30% or more of the variations in yield. Since 1991, climate trends have significantly decreased yield trends in all crops but rice, leading to foregone production since 1981 of about 12 million tons per year of wheat or maize, representing an annual economic loss of $1.2 to $1.7 billion. At the global scale, negative impacts of climate trends on crop yields are already apparent. Annual global temperatures have increased by {approx}0.4 C since 1980, with even larger changes observed in several regions (1). While many studies have considered the impacts of future climate changes on food production (2-5), the effects of these past changes on agriculture remain unclear. It is likely that warming has improved yields in some areas, reduced them in others, and had negligible impacts in still others; the relative balance of these effects at the global scale is unknown. An understanding of this balance would help to anticipate impacts of future climate changes, as well as to more accurately assess recent (and thereby project future) technologically driven yield progress. Separating the contribution of climate from concurrent changes in other factors--such as crop cultivars, management practices, soil quality, and atmospheric carbon dioxide (CO{sub 2}) levels--requires models that describe the response of yields to climate. Studies of future global impacts of climate change have typically relied on a bottom-up approach, whereby field scale, process-based models are applied to hundreds of representative sites and then averaged (e.g., ref 2). Such approaches require input data on soil and management conditions, which are often difficult to obtain. Limitations on data quality or quantity can thus limit the utility of this approach

  14. Evaluating the Dominant Components of Warming in Pliocene Climate Simulations

    NASA Technical Reports Server (NTRS)

    Hill, D. J.; Haywood, A. M.; Lunt, D. J.; Hunter, S. J.; Bragg, F. J.; Contoux, C.; Stepanek, C.; Sohl, L.; Rosenbloom, N. A.; Chan, W.-L.; Kamae, Y.; Zhang, Z.; Abe-Ouchi, A.; Chandler, M. A.; Jost, A.; Lohmann, G.; Otto-Bliesner, B. L.; Ramstein, G.; Ueda, H.

    2014-01-01

    The Pliocene Model Intercomparison Project (PlioMIP) is the first coordinated climate model comparison for a warmer palaeoclimate with atmospheric CO2 significantly higher than pre-industrial concentrations. The simulations of the mid-Pliocene warm period show global warming of between 1.8 and 3.6 C above pre-industrial surface air temperatures, with significant polar amplification. Here we perform energy balance calculations on all eight of the coupled ocean-atmosphere simulations within PlioMIP Experiment 2 to evaluate the causes of the increased temperatures and differences between the models. In the tropics simulated warming is dominated by greenhouse gas increases, with the cloud component of planetary albedo enhancing the warming in most of the models, but by widely varying amounts. The responses to mid-Pliocene climate forcing in the Northern Hemisphere midlatitudes are substantially different between the climate models, with the only consistent response being a warming due to increased greenhouse gases. In the high latitudes all the energy balance components become important, but the dominant warming influence comes from the clear sky albedo, only partially offset by the increases in the cooling impact of cloud albedo. This demonstrates the importance of specified ice sheet and high latitude vegetation boundary conditions and simulated sea ice and snow albedo feedbacks. The largest components in the overall uncertainty are associated with clouds in the tropics and polar clear sky albedo, particularly in sea ice regions. These simulations show that albedo feedbacks, particularly those of sea ice and ice sheets, provide the most significant enhancements to high latitude warming in the Pliocene.

  15. Anthropogenic warming has increased drought risk in California

    PubMed Central

    Diffenbaugh, Noah S.; Swain, Daniel L.; Touma, Danielle

    2015-01-01

    California is currently in the midst of a record-setting drought. The drought began in 2012 and now includes the lowest calendar-year and 12-mo precipitation, the highest annual temperature, and the most extreme drought indicators on record. The extremely warm and dry conditions have led to acute water shortages, groundwater overdraft, critically low streamflow, and enhanced wildfire risk. Analyzing historical climate observations from California, we find that precipitation deficits in California were more than twice as likely to yield drought years if they occurred when conditions were warm. We find that although there has not been a substantial change in the probability of either negative or moderately negative precipitation anomalies in recent decades, the occurrence of drought years has been greater in the past two decades than in the preceding century. In addition, the probability that precipitation deficits co-occur with warm conditions and the probability that precipitation deficits produce drought have both increased. Climate model experiments with and without anthropogenic forcings reveal that human activities have increased the probability that dry precipitation years are also warm. Further, a large ensemble of climate model realizations reveals that additional global warming over the next few decades is very likely to create ∼100% probability that any annual-scale dry period is also extremely warm. We therefore conclude that anthropogenic warming is increasing the probability of co-occurring warm–dry conditions like those that have created the acute human and ecosystem impacts associated with the “exceptional” 2012–2014 drought in California. PMID:25733875

  16. Thermal adaptation of decomposer communities in warming soils

    PubMed Central

    Bradford, Mark A.

    2013-01-01

    Temperature regulates the rate of biogeochemical cycles. One way it does so is through control of microbial metabolism. Warming effects on metabolism change with time as physiology adjusts to the new temperature. I here propose that such thermal adaptation is observed in soil microbial respiration and growth, as the result of universal evolutionary trade-offs between the structure and function of both enzymes and membranes. I review the basis for these trade-offs and show that they, like substrate depletion, are plausible mechanisms explaining soil respiration responses to warming. I argue that controversies over whether soil microbes adapt to warming stem from disregarding the evolutionary physiology of cellular metabolism, and confusion arising from the term thermal acclimation to represent phenomena at the organism- and ecosystem-levels with different underlying mechanisms. Measurable physiological adjustments of the soil microbial biomass reflect shifts from colder- to warmer-adapted taxa. Hypothesized declines in the growth efficiency of soil microbial biomass under warming are controversial given limited data and a weak theoretical basis. I suggest that energy spilling (aka waste metabolism) is a more plausible mechanism for efficiency declines than the commonly invoked increase in maintenance-energy demands. Energy spilling has many fitness benefits for microbes and its response to climate warming is uncertain. Modeled responses of soil carbon to warming are sensitive to microbial growth efficiency, but declines in efficiency mitigate warming-induced carbon losses in microbial models and exacerbate them in conventional models. Both modeling structures assume that microbes regulate soil carbon turnover, highlighting the need for a third structure where microbes are not regulators. I conclude that microbial physiology must be considered if we are to have confidence in projected feedbacks between soil carbon stocks, atmospheric CO2, and climate change. PMID

  17. 40 CFR Table A-1 to Subpart A of... - Global Warming Potentials

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Global Warming Potentials A Table A-1... A-1 to Subpart A of Part 98—Global Warming Potentials Global Warming Potentials Name CAS No. Chemical formula Global warming potential(100 yr.) Carbon dioxide 124-38-9 CO2 1 Methane 74-82-8 CH4 a...

  18. Thai Youths and Global Warming: Media Information, Awareness, and Lifestyle Activities

    ERIC Educational Resources Information Center

    Chokriensukchai, Kanchana; Tamang, Ritendra

    2010-01-01

    This study examines the exposure of Thai youths to media information on global warming, the relationship between exposure to global warming information and awareness of global warming, and the relationship between that awareness and lifestyle activities that contribute to global warming. A focus group of eight Thai youths provided information that…

  19. 40 CFR Table A-1 to Subpart A of... - Global Warming Potentials

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Global Warming Potentials A Table A-1... A-1 to Subpart A of Part 98—Global Warming Potentials Global Warming Potentials Name CAS No. Chemical formula Global warming potential(100 yr.) Carbon dioxide 124-38-9 CO2 1 Methane 74-82-8 CH4...

  20. Artificial Warming of Arctic Meadow under Pollution Stress: Experimental design

    NASA Astrophysics Data System (ADS)

    Moni, Christophe; Silvennoinen, Hanna; Fjelldal, Erling; Brenden, Marius; Kimball, Bruce; Rasse, Daniel

    2014-05-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, notably because future warming is expected to be disproportionate as compared to world averages. Likewise, greenhouse gas (GHG) release from terrestrial ecosystems exposed to climate warming is expected to be the largest in the arctic. Artic agriculture, in the form of cultivated grasslands, is a unique and economically relevant feature of Northern Norway (e.g. Finnmark Province). In Eastern Finnmark, these agro-ecosystems are under the additional stressor of heavy metal and sulfur pollution generated by metal smelters of NW Russia. Warming and its interaction with heavy metal dynamics will influence meadow productivity, species composition and GHG emissions, as mediated by responses of soil microbial communities. Adaptation and mitigation measurements will be needed. Biochar application, which immobilizes heavy metal, is a promising adaptation method to promote positive growth response in arctic meadows exposed to a warming climate. In the MeadoWarm project we conduct an ecosystem warming experiment combined to biochar adaptation treatments in the heavy-metal polluted meadows of Eastern Finnmark. In summary, the general objective of this study is twofold: 1) to determine the response of arctic agricultural ecosystems under environmental stress to increased temperatures, both in terms of plant growth, soil organisms and GHG emissions, and 2) to determine if biochar application can serve as a positive adaptation (plant growth) and mitigation (GHG emission) strategy for these ecosystems under warming conditions. Here, we present the experimental site and the designed open-field warming facility. The selected site is an arctic meadow located at the Svanhovd Research station less than 10km west from the Russian mining city of Nikel. A splitplot design with 5 replicates for each treatment is used to test the effect of biochar amendment and a 3oC warming on the Arctic meadow. Ten circular

  1. Using Updated Climate Accounting to Slow Global Warming Before 2035

    NASA Astrophysics Data System (ADS)

    Schultz, T.

    2015-12-01

    The current and projected worsening of climate impacts make clear the urgency of limiting the global mean temperature to 2°C over preindustrial levels. But while mitigation policy today may slow global warming at the end of the century, it will not keep global warming within these limits. This failure arises in large part from the climate accounting system used to inform this policy, which does not factor in several scientific findings from the last two decades, including: The urgent need to slow global warming before 2035. This can postpone the time the +1.5°C limit is passed, and is the only way to avoid the most serious long-term climate disruptions. That while it may mitigate warming by the end of the century, reducing emissions of CO2 alone, according to UNEP/WMO[1], will do "little to mitigate warming over the next 20-30 years," and "may temporarily enhance near-term warming as sulfate [cooling] is reduced." That the only emissions reductions that can slow warming before 2035 are focused on short-lived climate pollutants. A small increase in current mitigation funding could fund these projects, the most promising of which target emissions in regional climate "hot spots" like the Arctic and India.[2] To ensure policies can effectively slow global warming before 2035, a new climate accounting system is needed. Such an updated system is being standardized in the USA,[3] and has been proposed for use in ISO standards. The key features of this updated system are: consideration of all climate pollutants and their multi-faceted climate effects; use of time horizons which prioritize mitigation of near-term warming; a consistent and accurate accounting for "biogenic" CO2; protocols ensuring that new scientific findings are incorporated; and a distinct accounting for emissions affecting regional "hot spots". This accounting system also considers environmental impacts outside of climate change, a feature necessary to identify "win-win" projects with climate benefits

  2. Is cold or warm blood cardioplegia superior for myocardial protection?

    PubMed

    Abah, Udo; Garfjeld Roberts, Patrick; Ishaq, Muhammad; De Silva, Ravi

    2012-06-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the use of warm or cold blood cardioplegia has superior myocardial protection. More than 192 papers were found using the reported search, of which 20 represented the best evidence to answer the clinical question. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. A good breadth of high-level evidence addressing this clinical dilemma is available, including a recent meta-analysis and multiple large randomized clinical trials. Yet despite this level of evidence, no clear significant clinical benefit has been demonstrated by warm or cold blood cardioplegia. This suggests that neither method is significantly superior and that both provide similar efficacy of myocardial protection. The meta-analysis, including 41 randomized control trials (5879 patients in total), concluded that although a lower cardiac enzyme release and improved postoperative cardiac index was demonstrated in the warm cardioplegia group, this benefit was not reflected in clinical outcomes, which were similar in both groups. This theme of benefit in biochemical markers, physiological metrics and non-fatal postoperative events in the warm cardioplegia group ran throughout the literature, in particular the 'Warm Heart investigators' who conducted a randomized trial of 1732 patients, demonstrated a reduction in postoperative low output syndrome (6.1 versus 9.3%, P = 0.01) in the warm cardioplegia group, but no significant drop in 30-day all-cause mortality (1.4 versus 2.5%, P = 0.12). However, their later follow-up indicates non-fatal postoperative events predict reduced late survival, independent of cardioplegia. A minority of studies suggested a benefit of cold cardioplegia over warm in particular patient subgroups: One group conducted a retrospective study of 520 patients who

  3. Passive nighttime warming facility for forest ecosystem research.

    PubMed

    Luxmoore, R. J.; Hanson, P. J.; Beauchamp, J. J.; Joslin, J. D.

    1998-01-01

    A nighttime warming experiment is proposed. Over the last four decades a significant rise in nighttime minimum temperature has been determined from analysis of meteorological records from a global distribution of locations. The experiment involves nighttime deployment of infrared (IR) reflecting curtains around four sides of a forest canopy and across the top of the forest to mimic the top-down warming effect of cloud cover. The curtains are deployed with cable and pulley systems mounted on a tower and scaffolding structure built around the selected forest site. The trunk space is not enclosed except as an optional manipulation. The curtains reflect long-wave radiation emitted from the forest and ground back into the forest warming the trees, litter, and soil. Excellent infrared reflection can be obtained with commercially available fabrics that have aluminum foil bonded to one side. A canopy warming of 3 to 5 degrees C is expected on cloudless nights, and on cloudy nights, a warming of 1 to 3 degrees C is anticipated relative to a control plot. The curtains are withdrawn by computer control during the day and also at night during periods with precipitation or excessive wind. Examples of hypothesized ecosystem responses to nighttime warming include: (1) increase in tree maintenance respiration (decreasing carbon reserves and ultimately tree growth), (2) increase in the length of the growing season (increasing growth), (3) increase in soil respiration, (4) increase in litter decomposition, (5) increase in mineralization of N and other nutrients from soil organic matter, (6) increase in nutrient uptake (increasing growth), and (7) increase in N immobilization in litter. Hypothesis 1 has the opposite consequence for tree growth to Hypotheses 2 and 6, and thus opposite consequences for the feedback regulation that vegetation has on net greenhouse gas releases to the atmosphere. If Hypothesis 1 is dominant, warming could lead to more warming from the additional CO(2

  4. Global warming: Perspectives from the Late Quaternary paleomammal record

    SciTech Connect

    Graham, R.W. )

    1993-03-01

    Global warming at the end of the Pleistocene caused significant environmental changes that directly and indirectly effected biotic communities. The biotic response to this global warming event can provide insights into the processes that might be anticipated for future climatic changes. The megafauna extinction may have been the most dramatic alteration of mammalian communities at the end of the Pleistocene. Late Quaternary warming also altered regional diversity patterns for some small mammal guilds without extinction. Reductions in body size for both small and large mammal species were also consequences of these environmental fluctuations. Geographic shifts in the distributions of individual mammal species resulted in changes in species composition of mammalian communities. The individualistic response of biota to environmental fluctuations define some boundary conditions for modeling communities. Understanding these boundary conditions is mandatory in planning for the preservation of biodiversity in the future. Finally, it is essential to determine how global warming will alter seasonal patterns because it is apparent from the paleobiological record that not all Quaternary warming events have been the same.

  5. Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection

    PubMed Central

    Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

    2016-01-01

    Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection. PMID:26838053

  6. Elevated CO2 further lengthens growing season under warming conditions.

    PubMed

    Reyes-Fox, Melissa; Steltzer, Heidi; Trlica, M J; McMaster, Gregory S; Andales, Allan A; LeCain, Dan R; Morgan, Jack A

    2014-06-12

    Observations of a longer growing season through earlier plant growth in temperate to polar regions have been thought to be a response to climate warming. However, data from experimental warming studies indicate that many species that initiate leaf growth and flowering earlier also reach seed maturation and senesce earlier, shortening their active and reproductive periods. A conceptual model to explain this apparent contradiction, and an analysis of the effect of elevated CO2--which can delay annual life cycle events--on changing season length, have not been tested. Here we show that experimental warming in a temperate grassland led to a longer growing season through earlier leaf emergence by the first species to leaf, often a grass, and constant or delayed senescence by other species that were the last to senesce, supporting the conceptual model. Elevated CO2 further extended growing, but not reproductive, season length in the warmed grassland by conserving water, which enabled most species to remain active longer. Our results suggest that a longer growing season, especially in years or biomes where water is a limiting factor, is not due to warming alone, but also to higher atmospheric CO2 concentrations that extend the active period of plant annual life cycles.

  7. The Hydrological Cycle Response to Rapid vs. Slow Global Warming

    NASA Astrophysics Data System (ADS)

    Russ, K. L.; Back, L. E.; Liu, Z.; Inoue, K.; Otto-Bliesner, B. L.

    2012-12-01

    Held and Soden (2006) compared climate simulations of the 21st century included in the 4th Assessment Report of the IPCC (2007). All showed an increase of about 7.5% in globally averaged water vapor for each degree Celsius (C°) increase in globally averaged surface temperature. This result was thought to be explained by plugging a representative surface or lower tropospheric temperature into the Clausius-Clapeyron relationship. We find this is not the case for a 22,000-year paleoclimate simulation, where water vapor increases at a rate of only 4.2% per C°. This is not due to relative humidity changes or differences in absolute temperature. Instead, this is due to the geographic pattern of warming during the paleoclimate. Most water vapor resides in the tropics and 1 K of global surface warming is relatively more concentrated in the tropics for rapid anthropogenic-like warming than for slow, paleoclimate warming. This is due to thermal inertia of the southern ocean. We conclude that the Clausius-Clapeyron relationship applied to surface temperature cannot by itself constrain the rate of change in globally averaged water vapor with globally averaged surface temperature. Thus we propose an alternate formula that applies more generally to warming scenarios.

  8. Characterizing Warm Molecular Hydrogen in Active Star-Forming Systems

    NASA Astrophysics Data System (ADS)

    Rangwala, Naseem

    2014-10-01

    Herschel observations of nearby star-forming galaxies have determined that the warm component of the molecular gas traced by the high-J CO lines dominates the luminosity (~90% of the total CO luminosity) and hence the energetics of the molecular ISM. At the temperatures (T = 300 - 2000 K) and densities (n_H < 1E6 per cubic cm) typically found in our survey, H2 emission is the dominant gas coolant, much more important than CO. A fundamental assumption of all analyses of CO emission has been that CO emission traces H2 over the entire range of physical conditions in the observed sources. However, a direct observational comparison of spatial distributions and kinematics of CO and H2 has never been made for the warm molecular gas. We propose to observe the warm H2, in S(1) and S(2) transitions, with the SOFIA-EXES instrument in a diverse sample of star-forming systems: NGC 253 (starburst nucleus), NGC 6240 (luminous infrared galaxy), NGC 1068 (Seyfert-2), and SgrB2(M)/(N) (Galactic hot cores). The primary goal is to compare these measurements with the warm CO (J = 6-5 transition) observed with the Atacama Large Millimeter Array (ALMA) to investigate differences in the kinematics and spatial distributions (for the extended targets) of the two molecules and thereby confirm whether CO is a reliable tracer of H2 in the warm gas.

  9. Global warming induced hybrid rainy seasons in the Sahel

    NASA Astrophysics Data System (ADS)

    Salack, Seyni; Klein, Cornelia; Giannini, Alessandra; Sarr, Benoit; Worou, Omonlola N.; Belko, Nouhoun; Bliefernicht, Jan; Kunstman, Harald

    2016-10-01

    The small rainfall recovery observed over the Sahel, concomitant with a regional climate warming, conceals some drought features that exacerbate food security. The new rainfall features include false start and early cessation of rainy seasons, increased frequency of intense daily rainfall, increasing number of hot nights and warm days and a decreasing trend in diurnal temperature range. Here, we explain these mixed dry/wet seasonal rainfall features which are called hybrid rainy seasons by delving into observed data consensus on the reduction in rainfall amount, its spatial coverage, timing and erratic distribution of events, and other atmospheric variables crucial in agro-climatic monitoring and seasonal forecasting. Further composite investigations of seasonal droughts, oceans warming and the regional atmospheric circulation nexus reveal that the low-to-mid-level atmospheric winds pattern, often stationary relative to either strong or neutral El-Niño-Southern-Oscillations drought patterns, associates to basin warmings in the North Atlantic and the Mediterranean Sea to trigger hybrid rainy seasons in the Sahel. More challenging to rain-fed farming systems, our results suggest that these new rainfall conditions will most likely be sustained by global warming, reshaping thereby our understanding of food insecurity in this region.

  10. Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection.

    PubMed

    Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

    2016-02-03

    Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection.

  11. Possible methane-induced polar warming in the early Eocene.

    PubMed

    Sloan, L C; Walker, J C; Moore, T C; Rea, D K; Zachos, J C

    1992-05-28

    Reconstructions of early Eocene climate depict a world in which the polar environments support mammals and reptiles, deciduous forests, warm oceans and rare frost conditions. At the same time, tropical sea surface temperatures are interpreted to have been the same as or slightly cooler than present values. The question of how to warm polar regions of Earth without noticeably warming the tropics remains unresolved; increased amounts of greenhouse gases would be expected to warm all latitudes equally. Oceanic heat transport has been postulated as a mechanism for heating high latitudes, but it is difficult to explain the dynamics that would achieve this. Here we consider estimates of Eocene wetland areas and suggest that the flux of methane, an important greenhouse gas, may have been substantially greater during the Eocene than at present. Elevated methane concentrations would have enhanced early Eocene global warming, and also might specifically have prevented severe winter cooling of polar regions because of the potential of atmospheric methane to promote the formation of optically thick, polar stratospheric ice clouds.

  12. Negative elevation-dependent warming trend in the Eastern Alps

    NASA Astrophysics Data System (ADS)

    Tudoroiu, M.; Eccel, E.; Gioli, B.; Gianelle, D.; Schume, H.; Genesio, L.; Miglietta, F.

    2016-04-01

    Mountain regions and the important ecosystem services they provide are considered to be very vulnerable to the current warming, and recent studies suggest that high-mountain environments experience more rapid changes in temperature than environments at lower elevations. Here we analysed weather records for the period 1975-2010 from the Eastern Italian Alps that show that warming occurred both at high and low elevations, but it was less pronounced at high elevations. This negative elevation-dependent trend was consistent for mean, maximum and minimum air temperature. Global radiation data measured at different elevations, surface energy fluxes measured above an alpine grassland and above a coniferous forest located at comparable elevations for nine consecutive years as well as remote sensing data (MODIS) for cloud cover and aerosol optical depth were analysed to interpret this observation. Increasing global radiation at low elevations turned out to be a potential driver of this negative elevation-dependent warming, but also contributions from land use and land cover changes at high elevations (abandonment of alpine pastures, expansion of secondary forest succession) were taken into account. We emphasise though, that a negative elevation-dependent warming is not universal and that future research and in particular models should not neglect the role of land use changes when determining warming rates over elevation.

  13. More data needed to support or disprove global warming theory

    SciTech Connect

    1997-05-26

    Reports of global warming are prevalent in the popular press. With the exception of Scandinavia, no major energy tax laws have been passed to date. But environmental pressures may change this, and the change could have a profound effect on refiners. These are the views of Gerald T. Westbrook, of TSBV Consultants, Houston. Westbrook summarized recent global-warming research, and his position on the subject, at the National Petroleum Refiners Association annual meeting, held March 16--18, in San Antonio. The greenhouse effect is real, says Westbrook. It is important, however, to distinguish between the two major mechanisms of the greenhouse effect: natural warming and anthropogenic warming (changes in the concentration of greenhouse gases caused by man). Without greenhouse gases the earth`s equilibrium temperature would be {minus}18 C. The effect of the gases is to raise the equilibrium temperature to 15 C. In the early 1980s, computer models estimated global warming over the past 100 years to be as much as 2.3 C. By 1986, those estimates had been reduced to 1.0 C, and in 1988, a range of 0.63 {+-} 0.2 C was reported. In 1995, a report by the Intergovernmental Panel on Climate change (IPCC) cited a range of 0.3--0.6 C. Westbrook asserts that the earth`s motion anomalies--orbit eccentricity, axial tilt, and wobbles--lead to dramatic changes in insolation, and are the dominant force over the last 160,000 years.

  14. Experimental Studies of the Transport Parameters of Warm Dense Matter

    SciTech Connect

    Chouffani, Khalid

    2014-12-01

    There is a need to establish fundamental properties of matter and energy under extreme physical conditions. Although high energy density physics (HEDP) research spans a wide range of plasma conditions, there is one unifying regime that is of particular importance and complexity: that of warm dense matter, the transitional state between solid state condensed matter and energetic plasmas. Most laboratory experimental conditions, including inertial confinement implosion, fall into this regime. Because all aspects of laboratory-created high-energy-density plasmas transition through the warm dense matter regime, understanding the fundamental properties to determine how matter and energy interact in this regime is an important aspect of major research efforts in HEDP. Improved understanding of warm dense matter would have significant and wide-ranging impact on HEDP science, from helping to explain wire initiation studies on the Sandia Z machine to increasing the predictive power of inertial confinement fusion modeling. The central goal or objective of our proposed research is to experimentally determine the electrical resistivity, temperature, density, and average ionization state of a variety of materials in the warm dense matter regime, without the use of theoretical calculations. Since the lack of an accurate energy of state (EOS) model is primarily due to the lack of experimental data, we propose an experimental study of the transport coefficients of warm dense matter.

  15. Warming caused by cumulative carbon emissions towards the trillionth tonne.

    PubMed

    Allen, Myles R; Frame, David J; Huntingford, Chris; Jones, Chris D; Lowe, Jason A; Meinshausen, Malte; Meinshausen, Nicolai

    2009-04-30

    Global efforts to mitigate climate change are guided by projections of future temperatures. But the eventual equilibrium global mean temperature associated with a given stabilization level of atmospheric greenhouse gas concentrations remains uncertain, complicating the setting of stabilization targets to avoid potentially dangerous levels of global warming. Similar problems apply to the carbon cycle: observations currently provide only a weak constraint on the response to future emissions. Here we use ensemble simulations of simple climate-carbon-cycle models constrained by observations and projections from more comprehensive models to simulate the temperature response to a broad range of carbon dioxide emission pathways. We find that the peak warming caused by a given cumulative carbon dioxide emission is better constrained than the warming response to a stabilization scenario. Furthermore, the relationship between cumulative emissions and peak warming is remarkably insensitive to the emission pathway (timing of emissions or peak emission rate). Hence policy targets based on limiting cumulative emissions of carbon dioxide are likely to be more robust to scientific uncertainty than emission-rate or concentration targets. Total anthropogenic emissions of one trillion tonnes of carbon (3.67 trillion tonnes of CO(2)), about half of which has already been emitted since industrialization began, results in a most likely peak carbon-dioxide-induced warming of 2 degrees C above pre-industrial temperatures, with a 5-95% confidence interval of 1.3-3.9 degrees C.

  16. Soil-carbon response to warming dependent on microbial physiology

    NASA Astrophysics Data System (ADS)

    Allison, Steven D.; Wallenstein, Matthew D.; Bradford, Mark A.

    2010-05-01

    Most ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon, producing a positive feedback to rising global temperatures. Although field experiments document an initial increase in the loss of CO2 from soils in response to warming, in line with these predictions, the carbon dioxide loss from soils tends to decline to control levels within a few years. This attenuation response could result from changes in microbial physiological properties with increasing temperature, such as a decline in the fraction of assimilated carbon that is allocated to growth, termed carbon-use efficiency. Here we explore these mechanisms using a microbial-enzyme model to simulate the responses of soil carbon to warming by 5∘C. We find that declines in microbial biomass and degradative enzymes can explain the observed attenuation of soil-carbon emissions in response to warming. Specifically, reduced carbon-use efficiency limits the biomass of microbial decomposers and mitigates the loss of soil carbon. However, microbial adaptation or a change in microbial communities could lead to an upward adjustment of the efficiency of carbon use, counteracting the decline in microbial biomass and accelerating soil-carbon loss. We conclude that the soil-carbon response to climate warming depends on the efficiency of soil microbes in using carbon.

  17. WARM-UP PROTOCOLS FOR HIGH SCHOOL STUDENTS.

    PubMed

    Chatzopoulos, Dimitris Eleytherios; Yiannakos, Athanasios; Kotzamanidou, Mariana; Bassa, Eleni

    2015-08-01

    The study compared the acute effects of three warm-up protocols on change-of-direction speed, reaction time, and movement time of upper extremities. Participants were 27 Greek high school students from an urban area (M age=17.2 yr., SD=0.2, range=16.5-18.0). All participants performed the following warm-up protocols on three different days: (a) 3 min. jogging followed by 5 min. static stretching, (b) 3 min. jogging followed by 5 min. dynamic stretching, and (c) 3 min. jogging followed by 5 min. of rest without stretching. At the end of each protocol, participants performed sprints of moderate to submaximal intensity. After the warm-up protocols, participants performed the following tests: "505-change-of-direction-speed," reaction time, and movement time (arm movements). There was no significant effect of protocols on the performance tests. Pre-exercise stretching may not be required for performance improvement in activities involving change-of-direction speed, reaction, and movement time if the final part of the warm-up involves sprinting. The advantage of a short duration warm-up is that it offers students more time to play in physical education lessons. However, it is generally important for students to learn the benefits of stretching and how to stretch for lifelong fitness.

  18. Warming can enhance invasion success through asymmetries in energetic performance.

    PubMed

    Penk, Marcin R; Jeschke, Jonathan M; Minchin, Dan; Donohue, Ian

    2016-03-01

    Both climate warming and biological invasions are prominent drivers of global environmental change and it is important to determine how they interact. However, beyond tolerance and reproductive thresholds, little is known about temperature dependence of invaders' performance, particularly in the light of competitive attributes of functionally similar native species. We used experimentally derived energy budgets and field temperature data to determine whether anticipated warming will asymmetrically affect the energy budgets of the globally invasive Ponto-Caspian mysid crustacean Hemimysis anomala and a functionally similar native competitor (Mysis salemaai) whose range is currently being invaded. In contrast to M. salemaai, which maintains a constant feeding rate with temperature leading to diminishing energy assimilation, we found that H. anomala increases its feeding rate with temperature in parallel with growing metabolic demand. This enabled the invader to maintain high energy assimilation rates, conferring substantially higher scope for growth compared to the native analogue at spring-to-autumn temperatures. Anticipated warming will likely exacerbate this energetic asymmetry and remove the winter overlap, which, given the seasonal limitation of mutually preferred prey, appears to underpin coexistence of the two species. These results indicate that temperature-dependent asymmetries in scope for growth between invaders and native analogues comprise an important mechanism determining invasion success under warming climates. They also highlight the importance of considering relevant spectra of ecological contexts in predicting successful invaders and their impacts under warming scenarios. PMID:26618450

  19. Myth or reality; Some data dispute global warming theory

    SciTech Connect

    Lee, R.W.

    1991-04-01

    Science in March 1990 published a National Aeronautics and Space Administration (NASA) analysis of data collected from 1979 through 1988 by the TIROS-N series of weather satellites. The data include the most precise global temperature measurements ever taken. The study found no evidence of global warming from the greenhouse effect during that period. If anything, the short-term trend was toward cooling, since the average of the first five years, 1979 to 1983, was warmer than the most recent five. The NASA findings can be added to a burgeoning body of scientific data seriously questioning the contention that Earth is threatened by global warming resulting from a greenhouse effect primarily instigated by man. Ironically, James Hansen, director of NASA's Goddard Institute for Space Studies, has been the nation's most outspoken advocate of the thesis that, because concentrations of carbon dioxide (CO{sub 2}) and other greenhouse gases, such as methane, have risen by 30 percent in the last 100 years and are expected to rise another 40 percent by 2050, the planet eventually will warm by about 4 degrees Celsius. According to this hypothesis, the warming will cause major coastal flooding, inland droughts and sundry other catastrophes. But Reid Bryson, founder of the Institute for Environmental Studies at the University of Wisconsin, contends Hansen's thesis cannot be accepted, and Michael Schlesinger, professor of meteorology at the University of Illinois, asserts the chance that global warming has already been detected is pretty close to zero.

  20. Impacts of climate warming on terrestrial ectotherms across latitude.

    PubMed

    Deutsch, Curtis A; Tewksbury, Joshua J; Huey, Raymond B; Sheldon, Kimberly S; Ghalambor, Cameron K; Haak, David C; Martin, Paul R

    2008-05-01

    The impact of anthropogenic climate change on terrestrial organisms is often predicted to increase with latitude, in parallel with the rate of warming. Yet the biological impact of rising temperatures also depends on the physiological sensitivity of organisms to temperature change. We integrate empirical fitness curves describing the thermal tolerance of terrestrial insects from around the world with the projected geographic distribution of climate change for the next century to estimate the direct impact of warming on insect fitness across latitude. The results show that warming in the tropics, although relatively small in magnitude, is likely to have the most deleterious consequences because tropical insects are relatively sensitive to temperature change and are currently living very close to their optimal temperature. In contrast, species at higher latitudes have broader thermal tolerance and are living in climates that are currently cooler than their physiological optima, so that warming may even enhance their fitness. Available thermal tolerance data for several vertebrate taxa exhibit similar patterns, suggesting that these results are general for terrestrial ectotherms. Our analyses imply that, in the absence of ameliorating factors such as migration and adaptation, the greatest extinction risks from global warming may be in the tropics, where biological diversity is also greatest.

  1. Surface measurements of global warming causing atmospheric constituents in Korea.

    PubMed

    Oh, S N; Youn, Y H; Park, K J; Min, H K; Schnell, R C

    2001-07-01

    The expansion of the industrial economy and the increase of population in Northeast Asian countries have caused much interest in climate monitoring related to global warming. However, new techniques and better platforms for the measurement of global warming and regional databases are still old-fashioned and are not being developed sufficiently. With respect to this agenda, since 1993, at the request of the World Meteorological Organization (WMO), to monitor functions of global warming, the Korea Meteorological Administration (KMA) has set up a Global Atmospheric Watch (GAW) Station on the western coast of Korea (Anmyun-do) and has been actively monitoring global warming over Northeast Asia. In addition, atmospheric carbon dioxide (CO2) has been measured for a similar KMA global warming program at Kosan, Cheju Island since 1990. Aerosol and radiation have also been measured at both sites as well as in Seoul. The observations have been analyzed using diagnostics of climate change in Northeast Asia and also have been internationally compared. Results indicate that greenhouse gases are in good statistic agreement with the NOAA/Climate Monitoring and Diagnostics Laboratory (CMDL) long-term trends of monthly mean concentrations and seasonal cycles. Atmospheric particulate matter has also been analyzed for particular Asian types in terms of optical depth, number concentration and size distribution.

  2. Clinical evaluation of a newly designed fluid warming kit on fluid warming and hypothermia during spinal surgery

    PubMed Central

    Jung, Ki Tae; So, Keum Young; So, Hyeong Jin; Shim, Soo Bin

    2015-01-01

    Background The Mega Acer Kit® (MAK) is a newly designed heated and humidified breathing circuit that warms fluid passing through the circuit lumen. In this study, we investigated the system's efficacy for the perioperative prevention of hypothermia and fluid warming. Methods Ninety patients undergoing spinal surgery were enrolled in this study and randomly assigned to 3 groups based on the fluid warming device used: no fluid warming system (Group C, n = 30), via a Standard Ranger (Group R, n = 30), or via the MAK (Group M, n = 30). Distal esophageal temperatures (Teso) and infusion fluid temperature (TF) were recorded at 15 min intervals for duration of 180 min during surgery. If Teso was < 35.0℃, a forced-air convective warming device was used. Results Final Teso values were 34.8 ± 0.3℃, 35.1 ± 0.1℃, and 35.8 ± 0.3℃ in groups C, R, and M, respectively (P < 0.01). Teso was significantly higher in group M when compared with that in groups C and R throughout the study period (P < 0.05). The number of patients requiring a forced-air convective warming device was significantly lower in group M (n = 0) when compared with that in groups R (n = 17) and C (n = 30) (P < 0.05). The final infusion fluid temperature was higher in group M when compared with that in groups C and R throughout the study period (35.4 ± 1.0 vs. 23.0 ± 0.3 and 32.8 ± 0.6℃; P < 0.01). Conclusions The MAK is more effective for preventing hypothermia and for warming fluid than the Standard Ranger. PMID:26495056

  3. Large stratospheric sudden warming in Antarctic late winter and shallow ozone hole in 1988

    SciTech Connect

    Kanzawa, Hiroshi; Kawaguchi, Sadao )

    1990-01-01

    There occurred a large stratospheric sudden warming in the southern hemisphere in late winter of 1988 which competes in suddenness and size with major mid-winter warmings in the northern hemisphere. Associated with the dynamical phenomenon of the sudden warming, total ozone increased over the eastern hemispheric part of Antarctica. The sudden warming as well as other warmings which followed it made the 1988 Antarctic ozone hole shallow in depth and small in area.

  4. Climate Warming and Disease Risks for Terrestrial and Marine Biota

    NASA Astrophysics Data System (ADS)

    Harvell, C. Drew; Mitchell, Charles E.; Ward, Jessica R.; Altizer, Sonia; Dobson, Andrew P.; Ostfeld, Richard S.; Samuel, Michael D.

    2002-06-01

    Infectious diseases can cause rapid population declines or species extinctions. Many pathogens of terrestrial and marine taxa are sensitive to temperature, rainfall, and humidity, creating synergisms that could affect biodiversity. Climate warming can increase pathogen development and survival rates, disease transmission, and host susceptibility. Although most host-parasite systems are predicted to experience more frequent or severe disease impacts with warming, a subset of pathogens might decline with warming, releasing hosts from disease. Recently, changes in El Niño-Southern Oscillation events have had a detectable influence on marine and terrestrial pathogens, including coral diseases, oyster pathogens, crop pathogens, Rift Valley fever, and human cholera. To improve our ability to predict epidemics in wild populations, it will be necessary to separate the independent and interactive effects of multiple climate drivers on disease impact.

  5. Climate warming and disease risks for terrestrial and marine biota

    USGS Publications Warehouse

    Harvell, C.D.; Mitchell, C.E.; Ward, J.R.; Altizer, S.; Dobson, A.P.; Ostfeld, R.S.; Samuel, M.D.

    2002-01-01

    Infectious diseases can cause rapid population declines or species extinctions. Many pathogens of terrestrial and marine taxa are sensitive to temperature, rainfall, and humidity, creating synergisms that could affect biodiversity. Climate warming can increase pathogen development and survival rates, disease transmission, and host susceptibility. Although most host-parasite systems are predicted to experience more frequent or severe disease impacts with warming, a subset of pathogens might decline with warming, releasing hosts from disease. Recently, changes in El Niño–Southern Oscillation events have had a detectable influence on marine and terrestrial pathogens, including coral diseases, oyster pathogens, crop pathogens, Rift Valley fever, and human cholera. To improve our ability to predict epidemics in wild populations, it will be necessary to separate the independent and interactive effects of multiple climate drivers on disease impact.

  6. Recent decrease in typhoon destructive potential and global warming implications

    PubMed Central

    Lin, I-I; Chan, Johnny C.L.

    2015-01-01

    Typhoons (tropical cyclones) severely impact the half-billion population of the Asian Pacific. Intriguingly, during the recent decade, typhoon destructive potential (Power Dissipation Index, PDI) has decreased considerably (by ∼35%). This decrease, paradoxically, has occurred despite the increase in typhoon intensity and ocean warming. Using the method proposed by Emanuel (in 2007), we show that the stronger negative contributions from typhoon frequency and duration, decrease to cancel the positive contribution from the increasing intensity, controlling the PDI. Examining the typhoons' environmental conditions, we find that although the ocean condition became more favourable (warming) in the recent decade, the atmospheric condition ‘worsened' at the same time. The ‘worsened' atmospheric condition appears to effectively overpower the ‘better' ocean conditions to suppress PDI. This stronger negative contribution from reduced typhoon frequency over the increased intensity is also present under the global warming scenario, based on analysis of the simulated typhoon data from high-resolution modelling. PMID:25990561

  7. Ion-ion dynamic structure factor of warm dense mixtures

    DOE PAGESBeta

    Gill, N. M.; Heinonen, R. A.; Starrett, C. E.; Saumon, D.

    2015-06-25

    In this study, the ion-ion dynamic structure factor of warm dense matter is determined using the recently developed pseudoatom molecular dynamics method [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. The method uses density functional theory to determine ion-ion pair interaction potentials that have no free parameters. These potentials are used in classical molecular dynamics simulations. This constitutes a computationally efficient and realistic model of dense plasmas. Comparison with recently published simulations of the ion-ion dynamic structure factor and sound speed of warm dense aluminum finds good to reasonable agreement. Using this method, we make predictions of the ion-ionmore » dynamical structure factor and sound speed of a warm dense mixture—equimolar carbon-hydrogen. This material is commonly used as an ablator in inertial confinement fusion capsules, and our results are amenable to direct experimental measurement.« less

  8. Ion-ion dynamic structure factor of warm dense mixtures

    SciTech Connect

    Gill, N. M.; Heinonen, R. A.; Starrett, C. E.; Saumon, D.

    2015-06-25

    In this study, the ion-ion dynamic structure factor of warm dense matter is determined using the recently developed pseudoatom molecular dynamics method [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. The method uses density functional theory to determine ion-ion pair interaction potentials that have no free parameters. These potentials are used in classical molecular dynamics simulations. This constitutes a computationally efficient and realistic model of dense plasmas. Comparison with recently published simulations of the ion-ion dynamic structure factor and sound speed of warm dense aluminum finds good to reasonable agreement. Using this method, we make predictions of the ion-ion dynamical structure factor and sound speed of a warm dense mixture—equimolar carbon-hydrogen. This material is commonly used as an ablator in inertial confinement fusion capsules, and our results are amenable to direct experimental measurement.

  9. Ocean's response to a CO/sub 2/-induced warming

    SciTech Connect

    Bryan, K.; Spelman, M.J.

    1985-11-20

    The effect of a large increase in atmospheric CO/sub 2/ on world climate was studied using a coupled ocean-atmosphere model. In particular, the predicted response of the ocean on the warming episode was considered. It was found that a fourfold increase in atmospheric CO/sub 2/ causes a warming effect of over 4 C, sufficient to produce a partial collapse of the thermohaline circulation (THC) of the ocean. It was inferred that as a result of the partial collapse of the THC the thermocline is able to sequester twice as much heat as would be predicted under normal climatic conditions, producing a negative feedback for greenhouse warming. However, the THC collapse would also affect the carbon cycle, possibly producing a feedback opposite to the effect of an increased heat uptake.

  10. Effect of respiratory warm-up on anaerobic power.

    PubMed

    Özdal, Mustafa; Bostanci, Özgür; Dağlioğlu, Önder; Ağaoğlu, Seydi Ahmet; Kabadayi, Menderes

    2016-07-01

    [Purpose] The aim of the present study was to examine the effects of respiratory muscle warm-up on anaerobic power. [Subjects and Methods] Thirty male field hockey players (age, 20.5 ± 2.0 years) each participated in a control (CAN) trial and an experimental (EAN) trial. The EAN trial involved respiratory muscle warm-up, while the CAN trial did not. Anaerobic power was measured using the Wingate protocol. Paired sample t-tests were used to compare the EAN and CAN trials. [Results] There were significant increases in peak power and relative peak power, and decreases in the time to peak after the EAN trial by 8.9%, 9.6%, and 28.8% respectively. [Conclusion] Respiratory muscle warm-up may positively affect anaerobic power due to faster attainment of peak power. PMID:27512273

  11. Structural Evolution of a Warm Frontal Precipitation Band During GCPEx

    NASA Technical Reports Server (NTRS)

    Colle, Brian A.; Naeger, Aaron; Molthan, Andrew; Nesbitt, Stephen

    2015-01-01

    A warm frontal precipitation band developed over a few hours 50-100 km to the north of a surface warm front. The 3-km WRF was able to realistically simulate band development, although the model is somewhat too weak. Band genesis was associated with weak frontogenesis (deformation) in the presence of weak potential and conditional instability feeding into the band region, while it was closer to moist neutral within the band. As the band matured, frontogenesis increased, while the stability gradually increased in the banding region. Cloud top generating cells were prevalent, but not in WRF (too stable). The band decayed as the stability increased upstream and the frontogenesis (deformation) with the warm front weakened. The WRF may have been too weak and short-lived with the band because too stable and forcing too weak (some micro issues as well).

  12. Stratospheric warmings: Synoptic, dynamic and general-circulation aspects

    NASA Technical Reports Server (NTRS)

    Mcinturff, R. M. (Editor)

    1978-01-01

    Synoptic descriptions consist largely of case studies, which involve a distinction between major and minor warmings. Results of energetics studies show the importance of tropospheric-stratospheric interaction, and the significance of the pressure-work term near the tropopause. Theoretical studies have suggested the role of wave-zonal flow interaction as well as nonlinear interaction between eddies, chemical and photochemical reactions, boundary forcing, and other factors. Numerical models have been based on such considerations, and these are discussed under various categories. Some indication is given as to why some of the models have been more successful than others in simulating warnings. The question of ozone and its role in warmings is briefly discussed. Finally, a broad view is taken of stratospheric warmings in relation to man's activities.

  13. Atmospheric sulfur hexafluoride - Sources, sinks and greenhouse warming

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien D.; Wang, Wei-Chyung; Shia, George; Goldman, Aaron; Murcray, Frank J.; Murcray, David G.; Rinsland, Curtis P.

    1993-01-01

    An estimate is obtained of worldwide production of SF6, from which a global emission rate is derived and extrapolated for the next 20 years. The atmospheric lifetime of SF6 is then estimated based on a known mechanism (e.g., photolysis and atmospheric oxidation) and/or on the mass balance method. Finally, the radiative forcing of SF6 is calculated based on recent laboratory IR absorption data, and the expected warming over the time period 1950-2010 is computed for several emission scenarios. Calculations showed that SF6 is 3 times more effective as a greenhouse gas compared to CFC 11 on a per-molecule basis. However, based on projected emission scenarios, the expected warming from SF6 through 2010 is small (0.004 C), compared to the warming from CO2 and other trace gases (0.8 C).

  14. Early emergence in a butterfly causally linked to anthropogenic warming.

    PubMed

    Kearney, Michael R; Briscoe, Natalie J; Karoly, David J; Porter, Warren P; Norgate, Melanie; Sunnucks, Paul

    2010-10-23

    There is strong correlative evidence that human-induced climate warming is contributing to changes in the timing of natural events. Firm attribution, however, requires cause-and-effect links between observed climate change and altered phenology, together with statistical confidence that observed regional climate change is anthropogenic. We provide evidence for phenological shifts in the butterfly Heteronympha merope in response to regional warming in the southeast Australian city of Melbourne. The mean emergence date for H. merope has shifted -1.5 days per decade over a 65-year period with a concurrent increase in local air temperatures of approximately 0.16°C per decade. We used a physiologically based model of climatic influences on development, together with statistical analyses of climate data and global climate model projections, to attribute the response of H. merope to anthropogenic warming. Such mechanistic analyses of phenological responses to climate improve our ability to forecast future climate change impacts on biodiversity.

  15. Effect of respiratory warm-up on anaerobic power

    PubMed Central

    Özdal, Mustafa; Bostanci, Özgür; Dağlioğlu, Önder; Ağaoğlu, Seydi Ahmet; Kabadayi, Menderes

    2016-01-01

    [Purpose] The aim of the present study was to examine the effects of respiratory muscle warm-up on anaerobic power. [Subjects and Methods] Thirty male field hockey players (age, 20.5 ± 2.0 years) each participated in a control (CAN) trial and an experimental (EAN) trial. The EAN trial involved respiratory muscle warm-up, while the CAN trial did not. Anaerobic power was measured using the Wingate protocol. Paired sample t-tests were used to compare the EAN and CAN trials. [Results] There were significant increases in peak power and relative peak power, and decreases in the time to peak after the EAN trial by 8.9%, 9.6%, and 28.8% respectively. [Conclusion] Respiratory muscle warm-up may positively affect anaerobic power due to faster attainment of peak power. PMID:27512273

  16. Changes in Terrestrial Water Availability under Global Warming

    NASA Astrophysics Data System (ADS)

    Lan, C. W.; Lo, M. H.; Chou, C.

    2014-12-01

    Under global warming, the annual range of precipitation is widening (Chou and Lan, 2012; Chou et al., 2013) and the frequency of precipitation extreme events also increases. Due to nonlinear responses of land hydrological process to precipitation extremes, runoff can increase exponentially, and on the hard hand, soil water storage may decline. In addition, IPCC AR5 indicates that soil moisture decreases in most areas under the global warming scenario. In this study, we use NCAR Community Land Model version 4 (CLM4) to simulate changes in terrestrial available water (TAW, defined as the precipitation minus evaporation minus runoff, and then divided by the precipitation) under global warming. Preliminary results show that the TAW has clear seasonal variations. Compared to previous studies, which do not include the runoff in the calculations of the available water, our estimates on the TAW has much less available water in high latitudes through out the year, especially under extreme precipitation events.

  17. CFC Destruction of Ozone - Major Cause of Recent Global Warming!

    NASA Astrophysics Data System (ADS)

    Ashworth, R. A.

    2008-12-01

    There has been a lot of discussion about global warming. Some say anthropogenic carbon dioxide (CO2) emissions caused the earth to warm. Others say there is no abnormality at all, that it is just natural warming. As you will see from the data presented and analyzed, a greater than normal warming did occur in recent times but no measurements confirm an increase in CO2, whether anthropogenic or natural, had any effect on global temperatures. There is however, strong evidence that anthropogenic emissions of chlorofluorocarbons (CFCs) were the major cause of the recent abnormal warming. CFCs have created both unnatural atmospheric cooling and warming based on these facts: CFCs have destroyed ozone in the lower stratosphere/ upper troposphere causing these zones in the atmosphere to cool 1.37°C from 1966 to 1998. This time span was selected to eliminate the effect of the natural solar irradiance (cooling-warming) cycle effect on the earth's temperature. The loss of ozone allowed more UV light to pass through the stratosphere at a sufficient rate to warm the lower troposphere plus 8-3/4" of the earth by 0.48°C (1966 to 1998). Mass and energy balances show that the energy that was absorbed in the lower stratosphere and upper troposphere hit the lower troposphere/earth at a sustainable level of 1.69 × 10 18 Btu more in 1998 than it did in 1966. Greater ozone depletion in the Polar Regions has caused these areas to warm some two and one-half (2 1/2) times that of the average earth temperature -1.2°C versus 0.48°C. This has caused permafrost to melt, which is releasing copious quantities of methane, estimated at 100 times that of manmade CO2 release, to the atmosphere. Methane in the atmosphere slowly converts to CO2 and water vapor and its release has contributed to higher CO2 concentrations in the atmosphere. There is a temperature anomaly in Antarctica. The Signey Island landmass further north, warmed like the rest of the Polar Regions; but south at Vostok, there has

  18. Root and Shoot Phenology May Respond Differently to Warming

    NASA Astrophysics Data System (ADS)

    Radville, L.; Eissenstat, D. M.; Post, E.

    2015-12-01

    Climate change is increasing temperatures and extending the growing season for many organisms. Shifts in phenology have been widely reported in response to global warming and have strong effects on ecosystem processes and greenhouse gas emissions. It is well understood that warming generally advances aboveground plant phenology, but the influence of temperature on root phenology is unclear. Most terrestrial biosphere models assume that root and shoot growth occur at the same time and are influenced by warming in the same way, but recent studies suggest that this may not be the case. Testing this assumption is particularly important in the Arctic where over 70% of plant biomass can be belowground and warming is happening faster than in other ecosystems. In 2013 and 2014 we examined the timing of root growth in the Arctic in plots that had been warmed or unwarmed for 10 years. We found that peak root growth occurred about one month before leaf growth, suggesting that spring root phenology is not controlled by carbon produced during spring photosynthesis. If root phenology is not controlled by photosynthate early in the season, earlier spring leaf growth may not cause earlier spring root growth. In support of this, we found that warming advanced spring leaf cover but did not significantly affect root phenology. Root growth was not significantly correlated with soil temperature and did not appear to be limited by near-freezing temperatures above the permafrost. These results suggest that although shoots are influenced by temperature, roots in this system may be more influenced by photosynthesis and carbon storage. Aboveground phenology, one of the most widely measured aspects of climate change, may not represent whole-plant phenology and may be a poor indicator of the timing of whole-plant carbon fluxes. Additionally, climate model assumptions that roots and shoots grow at the same time may need to be revised.

  19. Conservation Planning for Coral Reefs Accounting for Climate Warming Disturbances.

    PubMed

    Magris, Rafael A; Heron, Scott F; Pressey, Robert L

    2015-01-01

    Incorporating warming disturbances into the design of marine protected areas (MPAs) is fundamental to developing appropriate conservation actions that confer coral reef resilience. We propose an MPA design approach that includes spatially- and temporally-varying sea-surface temperature (SST) data, integrating both observed (1985-2009) and projected (2010-2099) time-series. We derived indices of acute (time under reduced ecosystem function following short-term events) and chronic thermal stress (rate of warming) and combined them to delineate thermal-stress regimes. Coral reefs located on the Brazilian coast were used as a case study because they are considered a conservation priority in the southwestern Atlantic Ocean. We show that all coral reef areas in Brazil have experienced and are projected to continue to experience chronic warming, while acute events are expected to increase in frequency and intensity. We formulated quantitative conservation objectives for regimes of thermal stress. Based on these objectives, we then evaluated if/how they are achieved in existing Brazilian MPAs and identified priority areas where additional protection would reinforce resilience. Our results show that, although the current system of MPAs incorporates locations within some of our thermal-stress regimes, historical and future thermal refugia along the central coast are completely unprotected. Our approach is applicable to other marine ecosystems and adds to previous marine planning for climate change in two ways: (i) by demonstrating how to spatially configure MPAs that meet conservation objectives for warming disturbance using spatially- and temporally-explicit data; and (ii) by strategically allocating different forms of spatial management (MPA types) intended to mitigate warming impacts and also enhance future resistance to climate warming. PMID:26535586

  20. Static and dynamic activity of warm receptors in Boa constrictor.

    PubMed

    Hensel, H

    1975-01-01

    Afferent impulses from multi- and single-fiber preparations of the trigeminal nerve in Boa constrictor were recorded during exactly controlled thermal stimulation of the receptive field in the labial region. At constant temperatures in the range between 18 and 37 degrees C, multi-fiber preparations showed a continuous discharge with a maximum around 30 degrees C. Dynamic warming caused a high increase of the discharge, whereas dynamic cooling led to a complete inhibition. No cold-sensitive fivers have been found. Mechanical stimulation elicited large spikes from specific mechanoreceptors. Single-fiber preparations from labial warm receptors did not respond to mechanical stimulation. Their discharge was always regular at constant temperatures. The average frequency of a warm receptor population was zero at about 18 degrees C, reached a maximum of 13 sec-1 at 30 degrees C and fell again to zero at 37 degrees C. In addition, a few warm receptors increased their static discharge with temperature up to 36 degrees C, the highest frequency being 38 sec-1. Stepwise warming by delta T = + 5 degrees C caused a marked overshoot in frequency, after which the discharge usually fell to a minimum and then rose again to a new static level. Stepwise cooling by delta T = MINUS 5 DEGREES C led to a transient inhibition of activity followed by an increase until the new static level was reached. In the first group of warm receptors the height of the dynamic overshoot varied with the adapting temperature, the largest average overshoot of 160 sec-1 occurring at an adapting temperature of 30 degrees C. These receptors have their static maximum as well as their highest dynamic sensitivity in the temperature range of the natural tropical habitat of Boidae.

  1. Global warming: knowledge and views of Iranian students.

    PubMed

    Yazdanparast, Taraneh; Salehpour, Sousan; Masjedi, Mohammad Reza; Seyedmehdi, Seyed Mohammad; Boyes, Eddie; Stanisstreet, Martin; Attarchi, Mirsaeed

    2013-04-06

    Study of students' knowledge about global warming can help authorities to have better imagination of this critical environmental problem. This research examines high school students' ideas about greenhouse effect and the results may be useful for the respective authorities to improve cultural and educational aspects of next generation. In this cross-sectional study, a 42 question questionnaire with mix of open and closed questions was used to evaluate high school students' view about the mechanism, consequences, causes and cures of global warming. To assess students' knowledge, cognitive score was also calculated. 1035 students were randomly selected from 19 educational districts of Tehran. Sampling method was multi stage. Only 5.1% of the students could explain greenhouse effect correctly and completely. 88.8% and 71.2% respectively believed "if the greenhouse effect gets bigger the Earth will get hotter" and "incidence of more skin cancers is a consequence of global warming". 69.6% and 68.8% respectively thought "the greenhouse effect is made worse by too much carbon dioxide" and "presence of ozone holes is a cause of greenhouse effect". 68.4% believed "not using cars so much is a cure for global warming". While a student's 'cognitive score' could range from -36 to +36, Students' mean cognitive score was equal to +1.64. Mean cognitive score of male students and grade 2 & 3 students was respectively higher than female ones (P<0.01) and grade 1 students (P<0.001) but there was no statistically significant difference between students of different regions (P>0.05). In general, students' knowledge about global warming was not acceptable and there were some misconceptions in the students' mind, such as supposing ozone holes as a cause and more skin cancer as a consequence of global warming. The Findings of this survey indicate that, this important stratum of society have been received no sufficient and efficient education and sensitization on this matter.

  2. Warming experiments underpredict plant phenological responses to climate change

    USGS Publications Warehouse

    Wolkovich, Elizabeth M.; Cook, Benjamin I.; Allen, Jenica M.; Crimmins, Theresa M.; Betancourt, Julio L.; Travers, Steven E.; Pau, Stephanie; Regetz, James; Davies, T. Jonathan; Kraft, Nathan J.B.; Ault, Toby R.; Bolmgren, Kjell; Mazer, Susan J.; McCabe, Gregory J.; McGill, Brian J.; Parmesan, Camille; Salamin, Nicolas; Schwartz, Mark D.; Cleland, Elsa E.

    2012-01-01

    Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

  3. Warming experiments underpredict plant phenological responses to climate change.

    PubMed

    Wolkovich, E M; Cook, B I; Allen, J M; Crimmins, T M; Betancourt, J L; Travers, S E; Pau, S; Regetz, J; Davies, T J; Kraft, N J B; Ault, T R; Bolmgren, K; Mazer, S J; McCabe, G J; McGill, B J; Parmesan, C; Salamin, N; Schwartz, M D; Cleland, E E

    2012-05-02

    Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

  4. Global warming: knowledge and views of Iranian students.

    PubMed

    Yazdanparast, Taraneh; Salehpour, Sousan; Masjedi, Mohammad Reza; Seyedmehdi, Seyed Mohammad; Boyes, Eddie; Stanisstreet, Martin; Attarchi, Mirsaeed

    2013-01-01

    Study of students' knowledge about global warming can help authorities to have better imagination of this critical environmental problem. This research examines high school students' ideas about greenhouse effect and the results may be useful for the respective authorities to improve cultural and educational aspects of next generation. In this cross-sectional study, a 42 question questionnaire with mix of open and closed questions was used to evaluate high school students' view about the mechanism, consequences, causes and cures of global warming. To assess students' knowledge, cognitive score was also calculated. 1035 students were randomly selected from 19 educational districts of Tehran. Sampling method was multi stage. Only 5.1% of the students could explain greenhouse effect correctly and completely. 88.8% and 71.2% respectively believed "if the greenhouse effect gets bigger the Earth will get hotter" and "incidence of more skin cancers is a consequence of global warming". 69.6% and 68.8% respectively thought "the greenhouse effect is made worse by too much carbon dioxide" and "presence of ozone holes is a cause of greenhouse effect". 68.4% believed "not using cars so much is a cure for global warming". While a student's 'cognitive score' could range from -36 to +36, Students' mean cognitive score was equal to +1.64. Mean cognitive score of male students and grade 2 & 3 students was respectively higher than female ones (P<0.01) and grade 1 students (P<0.001) but there was no statistically significant difference between students of different regions (P>0.05). In general, students' knowledge about global warming was not acceptable and there were some misconceptions in the students' mind, such as supposing ozone holes as a cause and more skin cancer as a consequence of global warming. The Findings of this survey indicate that, this important stratum of society have been received no sufficient and efficient education and sensitization on this matter. PMID:23605603

  5. Warming Experiments Underpredict Plant Phenological Responses to Climate Change

    NASA Technical Reports Server (NTRS)

    Wolkovich, E. M.; Cook, B. I.; Allen, J. M.; Crimmins, T. M.; Betancourt, J. L.; Travers, S. E.; Pau, S.; Regetz, J.; Davies, T. J.; Kraft, N. J. B.; Ault, T. R.; Bolmgren, K.; Mazer, S. J.; McCabe, G. J.; McGill, B. J.; Parmesan, C.; Salamin, N.; Schwartz, M. D.; Cleland, E. E.

    2012-01-01

    Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

  6. Conservation Planning for Coral Reefs Accounting for Climate Warming Disturbances.

    PubMed

    Magris, Rafael A; Heron, Scott F; Pressey, Robert L

    2015-01-01

    Incorporating warming disturbances into the design of marine protected areas (MPAs) is fundamental to developing appropriate conservation actions that confer coral reef resilience. We propose an MPA design approach that includes spatially- and temporally-varying sea-surface temperature (SST) data, integrating both observed (1985-2009) and projected (2010-2099) time-series. We derived indices of acute (time under reduced ecosystem function following short-term events) and chronic thermal stress (rate of warming) and combined them to delineate thermal-stress regimes. Coral reefs located on the Brazilian coast were used as a case study because they are considered a conservation priority in the southwestern Atlantic Ocean. We show that all coral reef areas in Brazil have experienced and are projected to continue to experience chronic warming, while acute events are expected to increase in frequency and intensity. We formulated quantitative conservation objectives for regimes of thermal stress. Based on these objectives, we then evaluated if/how they are achieved in existing Brazilian MPAs and identified priority areas where additional protection would reinforce resilience. Our results show that, although the current system of MPAs incorporates locations within some of our thermal-stress regimes, historical and future thermal refugia along the central coast are completely unprotected. Our approach is applicable to other marine ecosystems and adds to previous marine planning for climate change in two ways: (i) by demonstrating how to spatially configure MPAs that meet conservation objectives for warming disturbance using spatially- and temporally-explicit data; and (ii) by strategically allocating different forms of spatial management (MPA types) intended to mitigate warming impacts and also enhance future resistance to climate warming.

  7. Conservation Planning for Coral Reefs Accounting for Climate Warming Disturbances

    PubMed Central

    Magris, Rafael A.; Heron, Scott F.; Pressey, Robert L.

    2015-01-01

    Incorporating warming disturbances into the design of marine protected areas (MPAs) is fundamental to developing appropriate conservation actions that confer coral reef resilience. We propose an MPA design approach that includes spatially- and temporally-varying sea-surface temperature (SST) data, integrating both observed (1985–2009) and projected (2010–2099) time-series. We derived indices of acute (time under reduced ecosystem function following short-term events) and chronic thermal stress (rate of warming) and combined them to delineate thermal-stress regimes. Coral reefs located on the Brazilian coast were used as a case study because they are considered a conservation priority in the southwestern Atlantic Ocean. We show that all coral reef areas in Brazil have experienced and are projected to continue to experience chronic warming, while acute events are expected to increase in frequency and intensity. We formulated quantitative conservation objectives for regimes of thermal stress. Based on these objectives, we then evaluated if/how they are achieved in existing Brazilian MPAs and identified priority areas where additional protection would reinforce resilience. Our results show that, although the current system of MPAs incorporates locations within some of our thermal-stress regimes, historical and future thermal refugia along the central coast are completely unprotected. Our approach is applicable to other marine ecosystems and adds to previous marine planning for climate change in two ways: (i) by demonstrating how to spatially configure MPAs that meet conservation objectives for warming disturbance using spatially- and temporally-explicit data; and (ii) by strategically allocating different forms of spatial management (MPA types) intended to mitigate warming impacts and also enhance future resistance to climate warming. PMID:26535586

  8. Herbivores modify the carbon cycle in a warming arctic

    NASA Astrophysics Data System (ADS)

    Cahoon, S. M.; Sullivan, P.; Welker, J. M.; Post, E.

    2009-12-01

    Typically, our studies of arctic terrestrial ecosystem responses to changes in climate focus on abiotic drivers (i.e. warming or added rain or added snow) and subsequent biogeochemical cycles and plant physiological performance. However, many arctic systems, such as those in western Greenland, are home ranges for large herbivores such as muskoxen and caribou. In order to fully understand how tundra landscapes in Greenland will respond to change, experiments are needed that allow us to quantify whether abiotic (climate warming) and or biotic (presence or absence of herbivores) drivers or their combinations regulate ecosystem function and structure. Here we present the results of two consecutive field seasons in western Greenland in which we quantified the interactive effects of local herbivore foraging and simulated climate warming on ecosystem C and N cycling and leaf level physiology. Large exclosure fences were erected in 2002, and ITEX passive warming chambers were established in 2003 within and adjacent to the fences. We performed weekly CO2 flux measurements during the 2008 and 2009 growing seasons which we normalized to a common irradiance by generating light-response curves at all plots (n=9). Although we observed interannual variability in soil moisture and average daily air temperature, browsing by herbivores was a key factor in the seasonal carbon dynamics. By physically removing leaves and upper stems, caribou and muskoxen altered the community composition, reduced leaf area and in turn decreased gross ecosystem photosynthesis (GEP), regardless of the warming treatment. Neither herbivory nor warming significantly affected ecosystem respiration rates. Thus the reduction in net ecosystem exchange (NEE) was primarily driven by reductions in GEP associated with leaf area removal by grazers. Our results indicate that the biotic influence from large herbivores can significantly influence carbon-derived climatic feedbacks and can no longer be overlooked in

  9. How warm was Greenland during the last interglacial period?

    NASA Astrophysics Data System (ADS)

    Landais, Amaelle; Masson-Delmotte, Valérie; Capron, Emilie; Langebroek, Petra M.; Bakker, Pepijn; Stone, Emma J.; Merz, Niklaus; Raible, Christoph C.; Fischer, Hubertus; Orsi, Anaïs; Prié, Frédéric; Vinther, Bo; Dahl-Jensen, Dorthe

    2016-09-01

    The last interglacial period (LIG, ˜ 129-116 thousand years ago) provides the most recent case study of multimillennial polar warming above the preindustrial level and a response of the Greenland and Antarctic ice sheets to this warming, as well as a test bed for climate and ice sheet models. Past changes in Greenland ice sheet thickness and surface temperature during this period were recently derived from the North Greenland Eemian Ice Drilling (NEEM) ice core records, northwest Greenland. The NEEM paradox has emerged from an estimated large local warming above the preindustrial level (7.5 ± 1.8 °C at the deposition site 126 kyr ago without correction for any overall ice sheet altitude changes between the LIG and the preindustrial period) based on water isotopes, together with limited local ice thinning, suggesting more resilience of the real Greenland ice sheet than shown in some ice sheet models. Here, we provide an independent assessment of the average LIG Greenland surface warming using ice core air isotopic composition (δ15N) and relationships between accumulation rate and temperature. The LIG surface temperature at the upstream NEEM deposition site without ice sheet altitude correction is estimated to be warmer by +8.5 ± 2.5 °C compared to the preindustrial period. This temperature estimate is consistent with the 7.5 ± 1.8 °C warming initially determined from NEEM water isotopes but at the upper end of the preindustrial period to LIG temperature difference of +5.2 ± 2.3 °C obtained at the NGRIP (North Greenland Ice Core Project) site by the same method. Climate simulations performed with present-day ice sheet topography lead in general to a warming smaller than reconstructed, but sensitivity tests show that larger amplitudes (up to 5 °C) are produced in response to prescribed changes in sea ice extent and ice sheet topography.

  10. Changes in South Pacific rainfall bands in a warming climate

    NASA Astrophysics Data System (ADS)

    Widlansky, M. J.; Timmermann, A.; Stein, K.; McGregor, S.; Schneider, N.; England, M. H.; Lengaigne, M.; Cai, W.

    2012-12-01

    The South Pacific Convergence Zone (SPCZ) is the largest rainband in the Southern Hemisphere and provides most of the rainfall to Southwest Pacific island nations. In spite of various modeling efforts, it remains uncertain how the SPCZ will respond to greenhouse warming. A multi-model ensemble average of 21st century climate change projections from the current-generation of Coupled General Circulation Models (CGCMs) suggests a slightly wetter Southwest Pacific; however, inter-model uncertainty is greater than projected rainfall changes in the SPCZ region. Using a hierarchy of climate models we show that the uncertainty of SPCZ rainfall projections in the Southwest Pacific can be explained as a result of two competing mechanisms. Higher tropical sea surface temperatures (SST) lead to an overall increase of atmospheric moisture and rainfall while weaker SST gradients dynamically shift the SPCZ northeastward (see illustration) and promote summer drying in areas of the Southwest Pacific, similar to the response to strong El Niño events. Based on a multi-model ensemble of 55 greenhouse warming experiments and for moderate tropical warming of 2-3°C we estimate a 5% decrease of SPCZ rainfall, although uncertainty exceeds ±30% among CGCMs. For stronger tropical warming, a tendency for a wetter SPCZ region is identified.; Illustration of the "warmest gets wetter" response to projected 21st century greenhouse warming. Green shading depicts observed (1982-2009) rainfall during DJF (contour interval: 2 mm/day; starting at 1 mm/day). Blue (red) contours depict warming less (more) than the tropical mean (42.5°N/S) 21st century multi-model trend (contour interval: 0.2°C; starting at ±0.1°C).

  11. Component analysis report: Line shaft pump bushings, Warm Springs State Hospital, Warm Springs, Montana

    SciTech Connect

    McAlpin, Ron

    1981-03-01

    On 29 January 1981, the Failure Analysis Laboratory at Radian Corporation received two spider bushings from the State Hospital at Warm Springs, Montana, for metallurgical analysis. The bushings are from a 19 stage, 200 hp Worthington line shaft vertical turbine pump. The pump was set at 830 feet to test a low temperature geothermal well. One bushing was originally set near the top of the well; the other bushing had been set deep in the well. The bushings were reportedly manufactured from bronze sleeve-bearing material. After approximately 50 hours of intermittent operation, the pump began to experience severe vibration. The vibration appeared random in that it sometimes occurred immediately upon start up and other times occurred after several hours of operation. A Worthington service engineer tested the pump and made several recommendations to alleviate the problem. He concluded that excessive packing box friction, overloading, and shaft unscrewing caused the vibration. He also adjusted the vertical shaft and impeller clearances. The purposes of this analysis is to examine the shaft bushings for evidence of mechanical or corrosion damage that might have been related to the vibration problem.

  12. CLIMATE CHANGE: The Causes of 20th Century Warming.

    PubMed

    Zwiers, F W; Weaver, A J

    2000-12-15

    Global air surface temperatures increased by about 0.6 degrees C during the 20th century, but as Zwiers and Weaver discuss in their Perspective, the warming was not continuous. Two distinct periods of warming, from 1910 to 1945 and since 1976, were separated by a period of very gradual cooling. The authors highlight the work by Stott et al., who have performed the most comprehensive simulation of 20th century climate to date. The agreement between observed and simulated temperature variations strongly suggests that forcing from anthropogenic activities, moderated by variations in solar and volcanic forcing, has been the main driver of climate change during the past century.

  13. A note on antenna models in a warm isotropic plasma

    NASA Technical Reports Server (NTRS)

    Singh, N.

    1980-01-01

    The electron-transparent and electron-reflecting models of antennas in a warm isotropic plasma are reexamined. It is shown that a purely electrical treatment of both the models without an explicit use of the boundary condition on electron velocity yields the same results as those previously obtained through an electromechanical treatment. The essential difference between the two models is that for the electron-reflecting model, fields are nonzero only in the exterior region, while for the electron-transparent model, they are nonzero both in the exterior and interior regions of the antenna. This distinction helps in clarifying some misconceptions about these models of antennas in warm isotropic plasma.

  14. Global warming description using Daisyworld model with greenhouse gases.

    PubMed

    Paiva, Susana L D; Savi, Marcelo A; Viola, Flavio M; Leiroz, Albino J K

    2014-11-01

    Daisyworld is an archetypal model of the earth that is able to describe the global regulation that can emerge from the interaction between life and environment. This article proposes a model based on the original Daisyworld considering greenhouse gases emission and absorption, allowing the description of the global warming phenomenon. Global and local analyses are discussed evaluating the influence of greenhouse gases in the planet dynamics. Numerical simulations are carried out showing the general qualitative behavior of the Daisyworld for different scenarios that includes solar luminosity variations and greenhouse gases effect. Nonlinear dynamics perspective is of concern discussing a way that helps the comprehension of the global warming phenomenon.

  15. Theory and Simulation of Warm Dense Matter Targets

    SciTech Connect

    Barnard, J J; Armijo, J; More, R M; Friedman, A; Kaganovich, I; Logan, B G; Marinak, M M; Penn, G E; Sefkow, A B; Santhanam, P; Wurtele, J S

    2006-07-13

    We present simulations and analysis of the heating of warm dense matter foils by ion beams with ion energy less than one MeV per nucleon to target temperatures of order one eV. Simulations were carried out using the multi-physics radiation hydrodynamics code HYDRA and comparisons are made with analysis and the code DPC. We simulate possible targets for a proposed experiment at LBNL (the so-called Neutralized Drift Compression Experiment, NDCXII) for studies of warm dense matter. We compare the dynamics of ideally heated targets, under several assumed equation of states, exploring dynamics in the two-phase (fluid-vapor) regime.

  16. Changes in winter warming events in the Nordic Arctic Region

    NASA Astrophysics Data System (ADS)

    Vikhamar-Schuler, Dagrun; Isaksen, Ketil; Haugen, Jan Erik; Bjerke, Jarle Werner; Tømmervik, Hans

    2015-04-01

    In recent years winter warming events are frequently reported from Arctic areas. Extraordinarily warm weather episodes, occasionally combined with intense rainfall, cause severe ecological disturbance and great challenges for Arctic infrastructure. For example, the formation of ground ice due to winter rain or melting prevents reindeer from grazing, leads to vegetation browning, and impacts soil temperatures. The infrastructure may be affected by avalanches and floods resulting from intense snowmelt. The aim of our analysis is to study changes in warm spells during winter in the Nordic Arctic Region, here defined as the regions in Norway, Sweden and Finland north of the Arctic circle (66.5°N), including the Arctic islands Svalbard and Jan Mayen. Within this study area we have selected the longest available high quality observation series with daily temperature and precipitation. For studying future climate we use available regionally downscaled scenarios. We analyse three time periods: 1) the past 50-100 years, 2) the present (last 15 years, 2000-2014) and 3) the future (next 50-100 years). We define an extended winter season (October-April) and further divide it into three subseasons: 1) Early winter (October and November), 2) Mid-winter (December, January and February) and 3) Late-winter (March and April). We identify warm spells using two different classification criteria: a) days with temperature above 0°C (the melting temperature); and b) days with temperature in excess of the 90th percentile of the 1985-2014 temperature for each subseason. Both wet and dry warm spells are analysed. We compare the results for the mainland stations (maritime and inland stations) with the Arctic islands. All stations have very high frequency of warm weather events in the period 1930-1940s and for the last 15 years (2000-2014). For the most recent period the largest increase in number of warm spells are observed at the northernmost stations. We also find a continuation of this

  17. Singular perturbation methods and the warm plasma model

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Deschamps, G. A.

    1971-01-01

    The application of techniques of the singular perturbation theory to the analysis of warm plasma is discussed. Typically, the cold plasma model can be applied over wide ranges of parameters and only over narrow ranges forming so-called boundary layers is the warm plasma model used. Simplified equations can be used and the solutions matched on both sides of the layer's boundary. Simple examples to illustrate the solution are presented. The analysis confirms that some results are highly sensitive to the values of: (1) wire radius or gap size for an antenna, (2) temperature of the medium, and (3) incident angle of a plane wave.

  18. Global Warming - Myth or Reality?, The Erring Ways of Climatology

    NASA Astrophysics Data System (ADS)

    Leroux, Marcel

    In the global-warming debate, definitive answers to questions about ultimate causes and effects remain elusive. In Global Warming: Myth or Reality? Marcel Leroux seeks to separate fact from fiction in this critical debate from a climatological perspective. Beginning with a review of the dire hypotheses for climate trends, the author describes the history of the 1998 Intergovernmental Panel on Climate Change (IPCC) and many subsequent conferences. He discusses the main conclusions of the three IPCC reports and the predicted impact on global temperatures, rainfall, weather and climate, while highlighting the mounting confusion and sensationalism of reports in the media.

  19. Transition warming and cooling remanences in pyrrhotite and hematite

    NASA Astrophysics Data System (ADS)

    Dunlop, David J.

    2015-10-01

    Magnetic minerals acquire a remanent magnetization when cooled or warmed in an applied field H through a phase transition. This paper reports the first observations of transition cooling and warming remanent magnetizations (TrCRM and TrWRM) in pyrrhotite (Fe7S8) and hematite (αFe2O3), with phase transitions at 32 K (Besnus transition) and 250 K (Morin transition). TrWRM was produced by warming in a 2 mT field from 10 to 300 K and TrCRM by cooling in 2 mT from 300 to 10 K. In both experiments, magnetization M was measured at 5 K intervals. The largest changes in M occurred over a 20 K interval flanking the Besnus or Morin transition but substantial changes also occurred away from any transition, presumably due to continuous changes in anisotropy. The triclinic low-temperature phase of pyrrhotite has high remanence efficiency compared to the room-temperature monoclinic phase. When H was zeroed at 300 K, only 35-40% of M survived as TrWRM, but in TrCRM experiments when H was zeroed at 10 K, practically 100% of M was preserved. After zero-field cooling to 10 K, 50-60% of TrWRM was retained but <15% of TrCRM survived zero-field warming to 300 K. In hematite, both TrWRM of the room-temperature spin-canted phase and TrCRM of the low-temperature defect phase exist, as shown by net remanence production following complete warming-cooling or cooling-warming cycles between 10 and 300 K. Details of remanence acquisition/demagnetization in crossing the Morin transition could not be resolved, however. Symmetries were observed for both minerals. Single-domain size pyrrhotite crystals had mirror-image field-off and field-on warming curves below 32 K, during TrWRM production/TrCRM loss at the 32 K transition, and up to ≈150 K. Submicron single-domain hematite had almost complete symmetry between field-off and field-on curves during cooling as well as warming, both below and above the Morin transition but not in the transition region itself. This is the first time that mirror

  20. Quantifying global warming from the retreat of glaciers

    SciTech Connect

    Oerlemans, J. )

    1994-04-08

    Records of glacier fluctuations compiled by the World Glacier Monitoring Service can be used to derive an independent estimate of global warming during the last 100 years. Records of different glaciers are made comparable by a two-step scaling procedure; one allowing for differences in glacier geometry, the other for differences in climate sensitivity. The retreat of glaciers during the last 100 years appears to be coherent over the globe. On the basis of modeling of the climate sensitivity of glaciers, the observed glacier retreat can be explained by a linear warming trend of 0.66 kelvin per century.

  1. Penetration of human-induced warming into the world's oceans.

    PubMed

    Barnett, Tim P; Pierce, David W; Achutarao, Krishna M; Gleckler, Peter J; Santer, Benjamin D; Gregory, Jonathan M; Washington, Warren M

    2005-07-01

    A warming signal has penetrated into the world's oceans over the past 40 years. The signal is complex, with a vertical structure that varies widely by ocean; it cannot be explained by natural internal climate variability or solar and volcanic forcing, but is well simulated by two anthropogenically forced climate models. We conclude that it is of human origin, a conclusion robust to observational sampling and model differences. Changes in advection combine with surface forcing to give the overall warming pattern. The implications of this study suggest that society needs to seriously consider model predictions of future climate change.

  2. Theory of non-Gaussianity in warm inflation

    SciTech Connect

    Bastero-Gil, Mar; Berera, Arjun; Moss, Ian G.; Ramos, Rudnei O. E-mail: ab@ph.ed.ac.uk E-mail: rudnei@uerj.br

    2014-12-01

    The theory and methodology is developed to compute the bispectrum in warm inflation, leading to results for the non-linearity parameter and the shape of the bispectrum. Particular attention is paid to the study of the bispectrum in the regime of weak dissipation and how stochastic fluctuations affect the bispectrum. It is shown that, in contrast to the strong dissipative regime, the amplitude of non-Gaussianity is strongly dependent on the parameters governing the microscopic physics in the intermediate and weak dissipation warm inflation regimes. The most important results concern the shape of the bispectrum, which has two different, but distinct, forms in the weak and strong dissipative regimes.

  3. Warm Water and Cool Nests Are Best. How Global Warming Might Influence Hatchling Green Turtle Swimming Performance

    PubMed Central

    Booth, David T.; Evans, Andrew

    2011-01-01

    For sea turtles nesting on beaches surrounded by coral reefs, the most important element of hatchling recruitment is escaping predation by fish as they swim across the fringing reef, and as a consequence hatchlings that minimize their exposure to fish predation by minimizing the time spent crossing the fringing reef have a greater chance of surviving the reef crossing. One way to decrease the time required to cross the fringing reef is to maximize swimming speed. We found that both water temperature and nest temperature influence swimming performance of hatchling green turtles, but in opposite directions. Warm water increases swimming ability, with hatchling turtles swimming in warm water having a faster stroke rate, while an increase in nest temperature decreases swimming ability with hatchlings from warm nests producing less thrust per stroke. PMID:21826236

  4. Recent high mountain rockfalls and warm daily temperature extremes

    NASA Astrophysics Data System (ADS)

    Allen, S. K.; Huggel, C.

    2012-04-01

    Linkages between longer term warming of the climate, related changes in the cryosphere, and destabilisation of high mountain rockwalls have been documented in several studies. Although understanding is far from complete, a range of physical processes related to longer term warming are understood to have an effect on slope stability. More recently, some attention has turned to the possible influence of much shorter periods of extremely warm temperatures, as a contributing factor, or even trigger of slope failures. So far, studies have not extended beyond highlighting one or a few individual events, and no common approach to quantifying the 'extremity' of the prevailing temperatures has been used. In the current study, we integrate established practices used in the climatology community in the analyses of climate extremes, together with an inventory of ca. 20 recent rock failures (1987 - 2010) in the central European Alps, to assess temporal relationships between daily air temperature extremes and rock failure occurrence. Using data from three high elevation recording sites across Switzerland, we focus on daily maximum temperatures in the 4 weeks immediately prior to each rockfall occurrence, where an extremely warm day is defined as exceeding the 95th percentile during the climatological reference period of 1971 - 2000. The 95th percentile is calculated in a 21 day moving window, so that extreme temperatures are considered relative to the time of year, and not on an annual basis. In addition, rock failures from the Southern Alps of New Zealand are analysed, although high elevation climate data are limited from this region. Results from the European Alps show that a majority of recent slope failures have been preceded by one or more extreme, unseasonably warm days, most notably in the week immediately prior to the failure. For example, for 9 slope failures in the Valais - Mt Blanc region (based on Grand St Bernhard climate data), 6 were proceeded by extremely warm

  5. Climate warming and precipitation redistribution modify tree-grass interactions and tree species establishment in a warm-temperate savanna.

    PubMed

    Volder, Astrid; Briske, David D; Tjoelker, Mark G

    2013-03-01

    Savanna tree-grass interactions may be particularly sensitive to climate change. Establishment of two tree canopy dominants, post oak (Quercus stellata) and eastern redcedar (Juniperus virginiana), grown with the dominant C4 perennial grass (Schizachyrium scoparium) in southern oak savanna of the United States were evaluated under four climatic scenarios for 6 years. Tree-grass interactions were examined with and without warming (+1.5 °C) in combination with a long-term mean rainfall treatment and a modified rainfall regime that redistributed 40% of summer rainfall to spring and fall, intensifying summer drought. The aim was to determine: (1) the relative growth response of these species, (2) potential shifts in the balance of tree-grass interactions, and (3) the trajectory of juniper encroachment into savannas, under these anticipated climatic conditions. Precipitation redistribution reduced relative growth rate (RGR) of trees grown with grass. Warming increased growth of J. virginiana and strongly reduced Q. stellata survival. Tiller numbers of S. scoparium plants were unaffected by warming, but the number of reproductive tillers was increasingly suppressed by intensified drought each year. Growth rates of J. virginiana and Q. stellata were suppressed by grass presence early, but in subsequent years were higher when grown with grass. Quercus stellata had overall reduced RGR, but enhanced survival when grown with grass, while survival of J. virginiana remained near 100% in all treatments. Once trees surpassed a threshold height of 1.1 m, both tiller number and survival of S. scoparium plants were drastically reduced by the presence of J. virginiana, but not Q. stellata. Juniperus virginiana was the only savanna dominant in which neither survival nor final aboveground mass were adversely affected by the climate scenario of warming and intensified summer drought. These responses indicate that climate warming and altered precipitation patterns will further

  6. Ant-mediated seed dispersal in a warmed world

    PubMed Central

    Patterson, Courtney M.; Rodriguez-Cabal, Mariano A.; Ribbons, Relena R.; Dunn, Robert R.; Sanders, Nathan J.

    2014-01-01

    Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of eastern North America. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed dispersal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed. PMID:24688863

  7. Microstructural characterization of a warm-deformed microalloyed steel

    SciTech Connect

    Eghbali, B.

    2008-04-15

    A warm deformation process using torsion testing was carried out on a low carbon Nb-microalloyed steel. The physical processes that occur during deformation were studied by analyzing the warm flow curves. The mechanisms of fine ferrite grain formation were studied by means of optical microscopy and an electron back-scattering diffraction technique. The results show that warm flow curves of ferrite are similar to those affected only by dynamic softening events. Microstructural analysis shows that, with increasing strain, the new fine equiaxed ferrite grains surrounded by high-angle boundaries are generated at the initial boundaries. During the early stages of deformation, as strain increases the grain size decreases and the grain aspect ratio rapidly increases. A further increase of the strain also leads to continuous decreases of both the grain size and the grain aspect ratio. The dynamic softening mechanism and dynamical formation of new fine grains, observed during warm deformation, were verified to be due to continuous dynamic recrystallization.

  8. Climate warming and predation risk during herbivore ontogeny.

    PubMed

    Barton, Brandon T

    2010-10-01

    Phenological effects of climate change are expected to differ among species, altering interactions within ecological communities. However, the nature and strength of these effects can vary during ontogeny, so the net community-level effects will be the result of integration over an individual's lifetime. I resolved the mechanism driving the effects of warming and spider predation risk on a generalist grasshopper herbivore at each ontogenetic stage and quantified the treatment effects on a measure of reproductive fitness. Spiders caused nymphal grasshoppers to increase the proportion of herbs in their diet, thus having a positive indirect effect on grasses and a negative indirect effect on herbs. Warming strengthened the top-down effect by affecting spiders and grasshoppers differently. In cooler, ambient conditions, grasshoppers and spiders had a high degree of spatial overlap within the plant canopy. Grasshopper position was unaffected by temperature, but spiders moved lower in the canopy in response to warming. This decreased the spatial overlap between predator and prey, allowing nymphal grasshoppers to increase daily feeding time. While spiders decreased grasshopper growth and reproductive fitness in ambient conditions, spiders had no effect on grasshopper fitness in warmed treatments. The study demonstrates the importance of considering the ontogeny of behavior when examining the effects of climate change on trophic interactions. PMID:21058542

  9. The hiatus and accelerated warming decades in CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Song, Yi; Yu, Yongqiang; Lin, Pengfei

    2014-11-01

    Observed hiatus or accelerated warming phenomena are compared with numerical simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) archives, and the associated physical mechanisms are explored based on the CMIP5 models. Decadal trends in total ocean heat content (OHC) are strongly constrained by net top-of-atmosphere (TOA) radiation. During hiatus decades, most CMIP5 models exhibit a significant decrease in the SST and upper OHC and a significant increase of heat penetrating into the subsurface or deep ocean, opposite to the accelerated warming decades. The shallow meridional overturning of the Pacific subtropical cell experiences a significant strengthening (slowdown) for the hiatus (accelerated warming) decades associated with the strengthened (weakened) trade winds over the tropical Pacific. Both surface heating and ocean dynamics contribute to the decadal changes in SST over the Indian Ocean, and the Indonesian Throughflow has a close relationship with the changes of subsurface temperature in the Indian Ocean. The Atlantic Meridional Overturing Circulation (Antarctic Bottom Water) tends to weaken (strengthen) during hiatus decades, opposite to the accelerated warming decades. In short, the results highlight the important roles of air-sea interactions and ocean circulations for modulation of surface and subsurface temperature.

  10. Climatic warming and the future of bison as grazers.

    PubMed

    Craine, Joseph M; Towne, E Gene; Miller, Mary; Fierer, Noah

    2015-01-01

    Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores. PMID:26567987

  11. North Pacific deglacial hypoxic events linked to abrupt ocean warming.

    PubMed

    Praetorius, S K; Mix, A C; Walczak, M H; Wolhowe, M D; Addison, J A; Prahl, F G

    2015-11-19

    Marine sediments from the North Pacific document two episodes of expansion and strengthening of the subsurface oxygen minimum zone (OMZ) accompanied by seafloor hypoxia during the last deglacial transition. The mechanisms driving this hypoxia remain under debate. We present a new high-resolution alkenone palaeotemperature reconstruction from the Gulf of Alaska that reveals two abrupt warming events of 4-5 degrees Celsius at the onset of the Bølling and Holocene intervals that coincide with sudden shifts to hypoxia at intermediate depths. The presence of diatomaceous laminations and hypoxia-tolerant benthic foraminiferal species, peaks in redox-sensitive trace metals, and enhanced (15)N/(14)N ratio of organic matter, collectively suggest association with high export production. A decrease in (18)O/(16)O values of benthic foraminifera accompanying the most severe deoxygenation event indicates subsurface warming of up to about 2 degrees Celsius. We infer that abrupt warming triggered expansion of the North Pacific OMZ through reduced oxygen solubility and increased marine productivity via physiological effects; following initiation of hypoxia, remobilization of iron from hypoxic sediments could have provided a positive feedback on ocean deoxygenation through increased nutrient utilization and carbon export. Such a biogeochemical amplification process implies high sensitivity of OMZ expansion to warming.

  12. Human-caused Indo-Pacific warm pool expansion

    PubMed Central

    Weller, Evan; Min, Seung-Ki; Cai, Wenju; Zwiers, Francis W.; Kim, Yeon-Hee; Lee, Donghyun

    2016-01-01

    The Indo-Pacific warm pool (IPWP) has warmed and grown substantially during the past century. The IPWP is Earth’s largest region of warm sea surface temperatures (SSTs), has the highest rainfall, and is fundamental to global atmospheric circulation and hydrological cycle. The region has also experienced the world’s highest rates of sea-level rise in recent decades, indicating large increases in ocean heat content and leading to substantial impacts on small island states in the region. Previous studies have considered mechanisms for the basin-scale ocean warming, but not the causes of the observed IPWP expansion, where expansion in the Indian Ocean has far exceeded that in the Pacific Ocean. We identify human and natural contributions to the observed IPWP changes since the 1950s by comparing observations with climate model simulations using an optimal fingerprinting technique. Greenhouse gas forcing is found to be the dominant cause of the observed increases in IPWP intensity and size, whereas natural fluctuations associated with the Pacific Decadal Oscillation have played a smaller yet significant role. Further, we show that the shape and impact of human-induced IPWP growth could be asymmetric between the Indian and Pacific basins, the causes of which remain uncertain. Human-induced changes in the IPWP have important implications for understanding and projecting related changes in monsoonal rainfall, and frequency or intensity of tropical storms, which have profound socioeconomic consequences. PMID:27419228

  13. Add Yoga to Your Singing Warm-Ups

    ERIC Educational Resources Information Center

    Kuhn, Ivana Pinho

    2006-01-01

    Yoga has much to contribute to singing. The main physical disciplines of yoga are strength, flexibility, alignment, body awareness through breath control, and concentration. These basics also constitute the core of good singing. With instruction incorporated into the regular warm-up, one can introduce beginning yoga ideas into choir practice. Yoga…

  14. Hot Water and Warm Homes from Sunlight. Teacher's Guide.

    ERIC Educational Resources Information Center

    Gould, Alan

    A basic understanding of the potential of solar energy is increasingly relevant given the pollution caused by the burning of fossil fuel, health problems associated with that pollution, the possibility of global warming, and the complex issues raised by the dependence of industrialized nations on oil and natural gas. This teacher's guide presents…

  15. Warming will affect phytoplankton differently: evidence through a mechanistic approach

    PubMed Central

    Huertas, I. Emma; Rouco, Mónica; López-Rodas, Victoria; Costas, Eduardo

    2011-01-01

    Although the consequences of global warming in aquatic ecosystems are only beginning to be revealed, a key to forecasting the impact on aquatic communities is an understanding of individual species' vulnerability to increased temperature. Despite their microscopic size, phytoplankton support about half of the global primary production, drive essential biogeochemical cycles and represent the basis of the aquatic food web. At present, it is known that phytoplankton are important targets and, consequently, harbingers of climate change in aquatic systems. Therefore, investigating the capacity of phytoplankton to adapt to the predicted warming has become a relevant issue. However, considering the polyphyletic complexity of the phytoplankton community, different responses to increased temperature are expected. We experimentally tested the effects of warming on 12 species of phytoplankton isolated from a variety of environments by using a mechanistic approach able to assess evolutionary adaptation (the so-called ratchet technique). We found different degrees of tolerance to temperature rises and an interspecific capacity for genetic adaptation. The thermal resistance level reached by each species is discussed in relation to their respective original habitats. Our study additionally provides evidence on the most resistant phytoplankton groups in a future warming scenario. PMID:21508031

  16. Global warming triggers the loss of a key Arctic refugium.

    PubMed

    Rühland, K M; Paterson, A M; Keller, W; Michelutti, N; Smol, J P

    2013-12-01

    We document the rapid transformation of one of the Earth's last remaining Arctic refugia, a change that is being driven by global warming. In stark contrast to the amplified warming observed throughout much of the Arctic, the Hudson Bay Lowlands (HBL) of subarctic Canada has maintained cool temperatures, largely due to the counteracting effects of persistent sea ice. However, since the mid-1990s, climate of the HBL has passed a tipping point, the pace and magnitude of which is exceptional even by Arctic standards, exceeding the range of regional long-term variability. Using high-resolution, palaeolimnological records of algal remains in dated lake sediment cores, we report that, within this short period of intense warming, striking biological changes have occurred in the region's freshwater ecosystems. The delayed and intense warming in this remote region provides a natural observatory for testing ecosystem resilience under a rapidly changing climate, in the absence of direct anthropogenic influences. The environmental repercussions of this climate change are of global significance, influencing the huge store of carbon in the region's extensive peatlands, the world's southern-most polar bear population that depends upon Hudson Bay sea ice and permafrost for survival, and native communities who rely on this landscape for sustenance.

  17. Carbon Dioxide and Global Warming: A Failed Experiment

    ERIC Educational Resources Information Center

    Ribeiro, Carla

    2014-01-01

    Global warming is a current environmental issue that has been linked to an increase in anthropogenic carbon dioxide in the atmosphere. To raise awareness of the problem, various simple experiments have been proposed to demonstrate the effect of carbon dioxide on the planet's temperature. This article describes a similar experiment, which…

  18. Promotion of Scientific Literacy on Global Warming by Process Drama

    ERIC Educational Resources Information Center

    Pongsophon, Pongprapan; Yutakom, Naruemon; Boujaoude, Saouma B.

    2010-01-01

    This project aims to investigate how process drama promotes scientific literacy in the context of global warming. Thirty-one lower (n = 24) and upper (n = 7) secondary students of one secondary school in Bangkok, Thailand participated in a seven-day workshop which process drama strategy was implemented. In the workshop, the students were actively…

  19. Signature of ocean warming in global fisheries catch.

    PubMed

    Cheung, William W L; Watson, Reg; Pauly, Daniel

    2013-05-16

    Marine fishes and invertebrates respond to ocean warming through distribution shifts, generally to higher latitudes and deeper waters. Consequently, fisheries should be affected by 'tropicalization' of catch (increasing dominance of warm-water species). However, a signature of such climate-change effects on global fisheries catch has so far not been detected. Here we report such an index, the mean temperature of the catch (MTC), that is calculated from the average inferred temperature preference of exploited species weighted by their annual catch. Our results show that, after accounting for the effects of fishing and large-scale oceanographic variability, global MTC increased at a rate of 0.19 degrees Celsius per decade between 1970 and 2006, and non-tropical MTC increased at a rate of 0.23 degrees Celsius per decade. In tropical areas, MTC increased initially because of the reduction in the proportion of subtropical species catches, but subsequently stabilized as scope for further tropicalization of communities became limited. Changes in MTC in 52 large marine ecosystems, covering the majority of the world's coastal and shelf areas, are significantly and positively related to regional changes in sea surface temperature. This study shows that ocean warming has already affected global fisheries in the past four decades, highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions.

  20. Seventh Grade Students' Conceptions of Global Warming and Climate Change

    ERIC Educational Resources Information Center

    Shepardson, Daniel P.; Niyogi, Dev; Choi, Soyoung; Charusombat, Umarporn

    2009-01-01

    The purpose of this study was to investigate seventh grade students' conceptions of global warming and climate change. The study was descriptive in nature and involved the collection of qualitative data from 91 seventh grade students from three different schools in the Midwest, USA. An open response and draw and explain assessment instrument was…

  1. Global Warming: Discussion for EOS Science Writers Workshop

    NASA Technical Reports Server (NTRS)

    Hansen, James E

    1999-01-01

    The existence of global warming this century is no longer an issue of scientific debate. But there are many important questions about the nature and causes of long-term climate change, th roles of nature and human-made climate forcings and unforced (chaotic) climate variability, the practical impacts of climate change, and what, if anything, should be done to reduce global warming, Global warming is not a uniform increase of temperature, but rather involves at complex geographically varying climate change. Understanding of global warming will require improved observations of climate change itself and the forcing factors that can lead to climate change. The NASA Terra mission and other NASA Earth Science missions will provide key measurement of climate change and climate forcings. The strategy to develop an understanding of the causes and predictability of long-term climate change must be based on combination of observations with models and analysis. The upcoming NASA missions will make important contributions to the required observations.

  2. Climatic irregular staircases: generalized acceleration of global warming.

    PubMed

    De Saedeleer, Bernard

    2016-01-27

    Global warming rates mentioned in the literature are often restricted to a couple of arbitrary periods of time, or of isolated values of the starting year, lacking a global view. In this study, we perform on the contrary an exhaustive parametric analysis of the NASA GISS LOTI data, and also of the HadCRUT4 data. The starting year systematically varies between 1880 and 2002, and the averaging period from 5 to 30 yr - not only decades; the ending year also varies . In this way, we uncover a whole unexplored space of values for the global warming rate, and access the full picture. Additionally, stairstep averaging and linear least squares fitting to determine climatic trends have been sofar exclusive. We propose here an original hybrid method which combines both approaches in order to derive a new type of climatic trend. We find that there is an overall acceleration of the global warming whatever the value of the averaging period, and that 99.9% of the 3029 Earth's climatic irregular staircases are rising. Graphical evidence is also given that choosing an El Niño year as starting year gives lower global warming rates - except if there is a volcanic cooling in parallel. Our rates agree and generalize several results mentioned in the literature.

  3. Turkish Prospective Teachers' Understanding and Misunderstanding on Global Warming

    ERIC Educational Resources Information Center

    Ocal, A.; Kisoglu, M.; Alas, A.; Gurbuz, H.

    2011-01-01

    The key objective of this study is to determine the Turkish elementary prospective teachers' opinions on global warming. It is also aimed to establish prospective teachers' views about the environmental education in Turkish universities. A true-false type scale was administered to 564 prospective teachers from science education, social studies…

  4. A Noted Physicist's Contrarian View of Global Warming

    ERIC Educational Resources Information Center

    Goldstein, Evan R., Comp.

    2008-01-01

    According to Freeman Dyson, an emeritus professor of physics at the Institute for Advanced Study, the debate about global warming has become too narrow and opinions have become too entrenched. Relying on a computer model designed by the Yale University economist William D. Nordhaus, Dyson compared the effectiveness and economic feasibility of…

  5. Greenhouse warming: The uncertainties and the mitigation challenge

    SciTech Connect

    Princiotta, F.T.

    1995-12-31

    The authors attempt to shed light on several of the key issues associated with greenhouse warming. Using a relatively simple, but instructive, model, and information from a variety of credible sources, a number of issues are discussed: The model (Glowarm 3.0) that the author has developed to help evaluate these questions is a spreadsheet (Lotus 1-2-3) model which calculates global concentrations and their associated global warming contributions for all the major greenhouse gases: CO{sub 2}, CH{sub 4}, ozone precursors, nitrous oxide (N{sub 2}O), CFCs, and their substitutes. The model calculates atmospheric concentrations of greenhouse gases based on projected emissions in 10-year increments. For CO{sub 2}, look-up tables are used to relate the fraction of CO{sub 2} remaining in the atmosphere as a function of time after emission for two alternative CO{sub 2} life cycles. For the other gases, an inputed lifetime value is used. Average global equilibrium temperatures are calculated using lifetimes and radiative forcing functions described in Intergovernmental Panel on Climate Change (IPCC), 1990. Realized (or actual) temperature is estimated using an empirical correlation algorithm the authors developed based on general circulation model (GCM) results presented in IPCC, 1992. This approach uses a correlation which relates the rate of equilibrium warming over the period between the target year and 1980 to the ratio of actual to equilibrium warming. There are 16 figures included.

  6. Pacific Sea Level Rise Pattern and Global Warming Hiatus

    NASA Astrophysics Data System (ADS)

    Peyser, C.; Yin, J.; Landerer, F. W.

    2015-12-01

    We investigate the linkage between two notable features of climate change and sea level rise during the past decades: a slowdown in global warming (hiatus) and an east-west seesaw pattern of SLR in the Pacific. During the hiatus, the subsurface layer of the Pacific shows significant increase in ocean heat content along with a strong east-west gradient that is reflected in the seesaw pattern of Pacific SLR through the thermosteric effect. Control simulations from 38 climate models indicate that during periods of negative trend in global mean surface temperature (analogous to hiatus decades in a warming world), dynamic sea level increases in the western Pacific and decreases in the eastern Pacific. The opposite occurs during periods of positive temperature trends. Using a regression analysis of the model simulations along with sea-level measurements from satellite altimetry, we find that the recent change in the Pacific Ocean heat storage has suppressed potential surface warming since 1998. Our results suggest that a flip of the Pacific SLR seesaw would imply a resumption of surface warming and SLR acceleration along the U.S. West Coast.

  7. Human-caused Indo-Pacific warm pool expansion.

    PubMed

    Weller, Evan; Min, Seung-Ki; Cai, Wenju; Zwiers, Francis W; Kim, Yeon-Hee; Lee, Donghyun

    2016-07-01

    The Indo-Pacific warm pool (IPWP) has warmed and grown substantially during the past century. The IPWP is Earth's largest region of warm sea surface temperatures (SSTs), has the highest rainfall, and is fundamental to global atmospheric circulation and hydrological cycle. The region has also experienced the world's highest rates of sea-level rise in recent decades, indicating large increases in ocean heat content and leading to substantial impacts on small island states in the region. Previous studies have considered mechanisms for the basin-scale ocean warming, but not the causes of the observed IPWP expansion, where expansion in the Indian Ocean has far exceeded that in the Pacific Ocean. We identify human and natural contributions to the observed IPWP changes since the 1950s by comparing observations with climate model simulations using an optimal fingerprinting technique. Greenhouse gas forcing is found to be the dominant cause of the observed increases in IPWP intensity and size, whereas natural fluctuations associated with the Pacific Decadal Oscillation have played a smaller yet significant role. Further, we show that the shape and impact of human-induced IPWP growth could be asymmetric between the Indian and Pacific basins, the causes of which remain uncertain. Human-induced changes in the IPWP have important implications for understanding and projecting related changes in monsoonal rainfall, and frequency or intensity of tropical storms, which have profound socioeconomic consequences.

  8. Climatic warming and the future of bison as grazers

    NASA Astrophysics Data System (ADS)

    Craine, Joseph M.; Towne, E. Gene; Miller, Mary; Fierer, Noah

    2015-11-01

    Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores.

  9. Climate warming and predation risk during herbivore ontogeny.

    PubMed

    Barton, Brandon T

    2010-10-01

    Phenological effects of climate change are expected to differ among species, altering interactions within ecological communities. However, the nature and strength of these effects can vary during ontogeny, so the net community-level effects will be the result of integration over an individual's lifetime. I resolved the mechanism driving the effects of warming and spider predation risk on a generalist grasshopper herbivore at each ontogenetic stage and quantified the treatment effects on a measure of reproductive fitness. Spiders caused nymphal grasshoppers to increase the proportion of herbs in their diet, thus having a positive indirect effect on grasses and a negative indirect effect on herbs. Warming strengthened the top-down effect by affecting spiders and grasshoppers differently. In cooler, ambient conditions, grasshoppers and spiders had a high degree of spatial overlap within the plant canopy. Grasshopper position was unaffected by temperature, but spiders moved lower in the canopy in response to warming. This decreased the spatial overlap between predator and prey, allowing nymphal grasshoppers to increase daily feeding time. While spiders decreased grasshopper growth and reproductive fitness in ambient conditions, spiders had no effect on grasshopper fitness in warmed treatments. The study demonstrates the importance of considering the ontogeny of behavior when examining the effects of climate change on trophic interactions.

  10. Tolerance limit for fish growth exceeded by warming waters

    NASA Astrophysics Data System (ADS)

    Neuheimer, A. B.; Thresher, R. E.; Lyle, J. M.; Semmens, J. M.

    2011-05-01

    Climate change can affect organisms both directly, by affecting their physiology, growth, and behaviour, and indirectly, for example through effects on ecosystem structure and function. For ectotherms, or `cold-blooded' animals, warming will directly affect their metabolism, with growth rates in temperate species predicted to increase initially as temperatures rise, but then decline as individuals struggle to maintain cardiac function and respiration in the face of increased metabolic demands. We provide evidence consistent with this prediction for a marine fish (Cheilodactylus spectabilis) in the Tasman Sea; one of the most rapidly warming regions of the Southern Hemisphere ocean. We estimated changes in the species' growth rate over a 90-year period using otoliths--bony structures that fish use for orientation and detection of movement--and compared these changes to temperature trends across the species' distribution. Increasing temperatures coincide with increased growth for populations in the middle of the species range, but with reduced growth for those at the warm northern edge of the species' distribution, indicating that temperatures may have already reached levels associated with increased metabolic costs. If warming continues, the direct metabolic effects of increasing temperatures on this species may lead to declining productivity and range contraction.

  11. Deep Arctic Ocean warming during the last glacial cycle

    USGS Publications Warehouse

    Cronin, T. M.; Dwyer, G.S.; Farmer, J.; Bauch, H.A.; Spielhagen, R.F.; Jakobsson, M.; Nilsson, J.; Briggs, W.M.; Stepanova, A.

    2012-01-01

    In the Arctic Ocean, the cold and relatively fresh water beneath the sea ice is separated from the underlying warmer and saltier Atlantic Layer by a halocline. Ongoing sea ice loss and warming in the Arctic Ocean have demonstrated the instability of the halocline, with implications for further sea ice loss. The stability of the halocline through past climate variations is unclear. Here we estimate intermediate water temperatures over the past 50,000 years from the Mg/Ca and Sr/Ca values of ostracods from 31 Arctic sediment cores. From about 50 to 11 kyr ago, the central Arctic Basin from 1,000 to 2,500 m was occupied by a water mass we call Glacial Arctic Intermediate Water. This water mass was 1–2 °C warmer than modern Arctic Intermediate Water, with temperatures peaking during or just before millennial-scale Heinrich cold events and the Younger Dryas cold interval. We use numerical modelling to show that the intermediate depth warming could result from the expected decrease in the flux of fresh water to the Arctic Ocean during glacial conditions, which would cause the halocline to deepen and push the warm Atlantic Layer into intermediate depths. Although not modelled, the reduced formation of cold, deep waters due to the exposure of the Arctic continental shelf could also contribute to the intermediate depth warming.

  12. Warming will affect phytoplankton differently: evidence through a mechanistic approach.

    PubMed

    Huertas, I Emma; Rouco, Mónica; López-Rodas, Victoria; Costas, Eduardo

    2011-12-01

    Although the consequences of global warming in aquatic ecosystems are only beginning to be revealed, a key to forecasting the impact on aquatic communities is an understanding of individual species' vulnerability to increased temperature. Despite their microscopic size, phytoplankton support about half of the global primary production, drive essential biogeochemical cycles and represent the basis of the aquatic food web. At present, it is known that phytoplankton are important targets and, consequently, harbingers of climate change in aquatic systems. Therefore, investigating the capacity of phytoplankton to adapt to the predicted warming has become a relevant issue. However, considering the polyphyletic complexity of the phytoplankton community, different responses to increased temperature are expected. We experimentally tested the effects of warming on 12 species of phytoplankton isolated from a variety of environments by using a mechanistic approach able to assess evolutionary adaptation (the so-called ratchet technique). We found different degrees of tolerance to temperature rises and an interspecific capacity for genetic adaptation. The thermal resistance level reached by each species is discussed in relation to their respective original habitats. Our study additionally provides evidence on the most resistant phytoplankton groups in a future warming scenario.

  13. Climatic warming and the future of bison as grazers.

    PubMed

    Craine, Joseph M; Towne, E Gene; Miller, Mary; Fierer, Noah

    2015-11-16

    Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores.

  14. Model finds bigger, stronger tropical cyclones with warming seas

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2014-03-01

    In the wake of powerful tropical cyclones such as Hurricanes Sandy and Katrina and Typhoon Haiyan, questions about the likely effect of climate change on tropical cyclone activity are on the public's mind. The interactions between global warming and cyclone activity, however, are complex, with rising sea surface temperatures, changing energy distributions, and altered atmospheric dynamics all having some effect.

  15. Global warming triggers the loss of a key Arctic refugium

    PubMed Central

    Rühland, K. M.; Paterson, A. M.; Keller, W.; Michelutti, N.; Smol, J. P.

    2013-01-01

    We document the rapid transformation of one of the Earth's last remaining Arctic refugia, a change that is being driven by global warming. In stark contrast to the amplified warming observed throughout much of the Arctic, the Hudson Bay Lowlands (HBL) of subarctic Canada has maintained cool temperatures, largely due to the counteracting effects of persistent sea ice. However, since the mid-1990s, climate of the HBL has passed a tipping point, the pace and magnitude of which is exceptional even by Arctic standards, exceeding the range of regional long-term variability. Using high-resolution, palaeolimnological records of algal remains in dated lake sediment cores, we report that, within this short period of intense warming, striking biological changes have occurred in the region's freshwater ecosystems. The delayed and intense warming in this remote region provides a natural observatory for testing ecosystem resilience under a rapidly changing climate, in the absence of direct anthropogenic influences. The environmental repercussions of this climate change are of global significance, influencing the huge store of carbon in the region's extensive peatlands, the world's southern-most polar bear population that depends upon Hudson Bay sea ice and permafrost for survival, and native communities who rely on this landscape for sustenance. PMID:24107529

  16. Fast-slow climate dynamics and peak global warming

    NASA Astrophysics Data System (ADS)

    Seshadri, Ashwin K.

    2016-06-01

    The dynamics of a linear two-box energy balance climate model is analyzed as a fast-slow system, where the atmosphere, land, and near-surface ocean taken together respond within few years to external forcing whereas the deep-ocean responds much more slowly. Solutions to this system are approximated by estimating the system's time-constants using a first-order expansion of the system's eigenvalue problem in a perturbation parameter, which is the ratio of heat capacities of upper and lower boxes. The solution naturally admits an interpretation in terms of a fast response that depends approximately on radiative forcing and a slow response depending on integrals of radiative forcing with respect to time. The slow response is inversely proportional to the "damping-timescale", the timescale with which deep-ocean warming influences global warming. Applications of approximate solutions are discussed: conditions for a warming peak, effects of an individual pulse emission of carbon dioxide (CO2 ), and metrics for estimating and comparing contributions of different climate forcers to maximum global warming.

  17. Broadband AC Conductivity of XUV Excited Warm Dense Gold

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Tsui, Y.; Toleikis, S.; Hering, P.; Brown, S.; Curry, C.; Tanikawa, T.; Hoeppner, H.; Levy, M.; Goede, S.; Ziaja-Motyka, B.; Rethfeld, B.; Recoules, Vanina; Ng, A.; Glenzer, S.

    2015-11-01

    The properties of ultrafast laser excited warm dense gold have been extensively studied in the past decade. In those studies, a 400nm ultrashort laser pulse was used to excite the 5 d electrons in gold to 6s/p state. Here we will present our recent study of warm dense gold with 245eV, 70fs pulses to selectively excite 4 f electrons using the XUV-FEL at FLASH. The AC conductivity of the warm dense gold was measured at different wavelengths (485nm, 520nm, 585nm, 640nm and 720nm) to cover the range from 5 d-6 s / p interband transitions to 6 s/ p intraband transitions. Preliminary result suggests that the onset of 5 d-6 s / p band transition shifts from 2.3eV to ~ 2eV, which is in agreement with the study of 400nm laser pulse excited warm dense gold. More detailed analysis of our data will also be presented.

  18. Rapid evolution of a Gulf Stream warm-core ring

    NASA Technical Reports Server (NTRS)

    Joyce, T.; Backus, R.; Cowles, T.; Baker, K.; Blackwelder, P.; Brown, O.; Evans, R.; Olson, D.; Fryxell, G.; Mountain, D.

    1984-01-01

    Satellite images are used to show that major alterations in the structure of Gulf Stream warm-core rings can occur during very short periods of two to five days when an interaction with the Gulf Stream is particularly intense. The role of these interactions in the evolution of a ring are discussed.

  19. Signature of ocean warming in global fisheries catch.

    PubMed

    Cheung, William W L; Watson, Reg; Pauly, Daniel

    2013-05-16

    Marine fishes and invertebrates respond to ocean warming through distribution shifts, generally to higher latitudes and deeper waters. Consequently, fisheries should be affected by 'tropicalization' of catch (increasing dominance of warm-water species). However, a signature of such climate-change effects on global fisheries catch has so far not been detected. Here we report such an index, the mean temperature of the catch (MTC), that is calculated from the average inferred temperature preference of exploited species weighted by their annual catch. Our results show that, after accounting for the effects of fishing and large-scale oceanographic variability, global MTC increased at a rate of 0.19 degrees Celsius per decade between 1970 and 2006, and non-tropical MTC increased at a rate of 0.23 degrees Celsius per decade. In tropical areas, MTC increased initially because of the reduction in the proportion of subtropical species catches, but subsequently stabilized as scope for further tropicalization of communities became limited. Changes in MTC in 52 large marine ecosystems, covering the majority of the world's coastal and shelf areas, are significantly and positively related to regional changes in sea surface temperature. This study shows that ocean warming has already affected global fisheries in the past four decades, highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions. PMID:23676754

  20. A Massive Warm Baryonic Halo in the Coma Cluster

    NASA Technical Reports Server (NTRS)

    Bonamente, Massimiliano; Joy, Marshall K.; Lieu, Richard

    2003-01-01

    Several deep PSPC observations of the Coma Cluster reveal a very large scale halo of soft X-ray emission, substantially in excess of the well-known radiation from the hot intracluster medium. The excess emission, previously reported in the central region of the cluster using lower sensitivity Extreme Ultraviolet Explorer (EUVE) and ROSAT data, is now evident out to a radius of 2.6 Mpc, demonstrating that the soft excess radiation from clusters is a phenomenon of cosmological significance. The X-ray spectrum at these large radii cannot be modeled nonthermally but is consistent with the original scenario of thermal emission from warm gas at approx. 10(exp 6) K. The mass of the warm gas is on par with that of the hot X-ray-emitting plasma and significantly more massive if the warm gas resides in low-density filamentary structures. Thus, the data lend vital support to current theories of cosmic evolution, which predict that at low redshift approx. 30%-40% of the baryons reside in warm filaments converging at clusters of galaxies.

  1. Global Warming on the International Agenda. Teaching Strategy.

    ERIC Educational Resources Information Center

    Keenan-Byrne, Patricia; Malkasian, Mark

    1997-01-01

    Presents a lesson plan that teaches students the links between industrialization and global warming, and analyzes the conflicting values and priorities involved in the debate between economic development and environmental concerns. Students role play delegates from countries attending an environmental conference. Handouts provide background…

  2. College Students' Misconceptions of Environmental Issues Related to Global Warming.

    ERIC Educational Resources Information Center

    Groves, Fred H.; Pugh, Ava F.

    Students are currently exposed to world environmental problems--including global warming and the greenhouse effect--in science classes at various points during their K-12 and college experience. However, the amount and depth of explosure to these issues can be quite variable. Students are also exposed to sources of misinformation leading to…

  3. Warming Up to STS. Activities to Encourage Environmental Awareness.

    ERIC Educational Resources Information Center

    Rosenthal, Dorothy B.

    1990-01-01

    Developed is an interdisciplinary unit that deals with global warming and the greenhouse effect. Included are 10 lessons that can be used to supplement existing plans or used as a basis for developing a new unit. Included are modeling, laboratory, graphing, role-playing, and discussion activities. (KR)

  4. Cooling and Warming Laws: An Exact Analytical Solution

    ERIC Educational Resources Information Center

    Besson, Ugo

    2010-01-01

    This paper deals with temperature variations over time of objects placed in a constant-temperature environment in the presence of thermal radiation. After a historical introduction, the paper discusses cooling and warming laws, by taking into account first solely object-environment energy exchange by thermal radiation, and then adding…

  5. Human-caused Indo-Pacific warm pool expansion.

    PubMed

    Weller, Evan; Min, Seung-Ki; Cai, Wenju; Zwiers, Francis W; Kim, Yeon-Hee; Lee, Donghyun

    2016-07-01

    The Indo-Pacific warm pool (IPWP) has warmed and grown substantially during the past century. The IPWP is Earth's largest region of warm sea surface temperatures (SSTs), has the highest rainfall, and is fundamental to global atmospheric circulation and hydrological cycle. The region has also experienced the world's highest rates of sea-level rise in recent decades, indicating large increases in ocean heat content and leading to substantial impacts on small island states in the region. Previous studies have considered mechanisms for the basin-scale ocean warming, but not the causes of the observed IPWP expansion, where expansion in the Indian Ocean has far exceeded that in the Pacific Ocean. We identify human and natural contributions to the observed IPWP changes since the 1950s by comparing observations with climate model simulations using an optimal fingerprinting technique. Greenhouse gas forcing is found to be the dominant cause of the observed increases in IPWP intensity and size, whereas natural fluctuations associated with the Pacific Decadal Oscillation have played a smaller yet significant role. Further, we show that the shape and impact of human-induced IPWP growth could be asymmetric between the Indian and Pacific basins, the causes of which remain uncertain. Human-induced changes in the IPWP have important implications for understanding and projecting related changes in monsoonal rainfall, and frequency or intensity of tropical storms, which have profound socioeconomic consequences. PMID:27419228

  6. Ant-mediated seed dispersal in a warmed world.

    PubMed

    Stuble, Katharine L; Patterson, Courtney M; Rodriguez-Cabal, Mariano A; Ribbons, Relena R; Dunn, Robert R; Sanders, Nathan J

    2014-01-01

    Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of eastern North America. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed dispersal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed. PMID:24688863

  7. Ant-mediated seed dispersal in a warmed world.

    PubMed

    Stuble, Katharine L; Patterson, Courtney M; Rodriguez-Cabal, Mariano A; Ribbons, Relena R; Dunn, Robert R; Sanders, Nathan J

    2014-01-01

    Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of eastern North America. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed dispersal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed.

  8. Global Warming: If You Can't Stand the Heat

    ERIC Educational Resources Information Center

    Baird, Stephen L.

    2005-01-01

    Global warming is the progressive, gradual rise of the earth's average surface temperature, thought to be caused in part by increased concentrations of "greenhouse" gases (GHGs) in the atmosphere. According to the National Academy of Sciences, the Earth's temperature has risen by about one degree Fahrenheit in the past century, with accelerated…

  9. Non-linear Langmuir waves in a warm quantum plasma

    SciTech Connect

    Dubinov, Alexander E. Kitaev, Ilya N.

    2014-10-15

    A non-linear differential equation describing the Langmuir waves in a warm quantum electron-ion plasma has been derived. Its numerical solutions of the equation show that ordinary electronic oscillations, similar to the classical oscillations, occur along with small-scale quantum Langmuir oscillations induced by the Bohm quantum force.

  10. North Pacific deglacial hypoxic events linked to abrupt ocean warming.

    PubMed

    Praetorius, S K; Mix, A C; Walczak, M H; Wolhowe, M D; Addison, J A; Prahl, F G

    2015-11-19

    Marine sediments from the North Pacific document two episodes of expansion and strengthening of the subsurface oxygen minimum zone (OMZ) accompanied by seafloor hypoxia during the last deglacial transition. The mechanisms driving this hypoxia remain under debate. We present a new high-resolution alkenone palaeotemperature reconstruction from the Gulf of Alaska that reveals two abrupt warming events of 4-5 degrees Celsius at the onset of the Bølling and Holocene intervals that coincide with sudden shifts to hypoxia at intermediate depths. The presence of diatomaceous laminations and hypoxia-tolerant benthic foraminiferal species, peaks in redox-sensitive trace metals, and enhanced (15)N/(14)N ratio of organic matter, collectively suggest association with high export production. A decrease in (18)O/(16)O values of benthic foraminifera accompanying the most severe deoxygenation event indicates subsurface warming of up to about 2 degrees Celsius. We infer that abrupt warming triggered expansion of the North Pacific OMZ through reduced oxygen solubility and increased marine productivity via physiological effects; following initiation of hypoxia, remobilization of iron from hypoxic sediments could have provided a positive feedback on ocean deoxygenation through increased nutrient utilization and carbon export. Such a biogeochemical amplification process implies high sensitivity of OMZ expansion to warming. PMID:26581293

  11. Missing feedbacks, asymmetric uncertainties, and theunderestimation of future warming

    SciTech Connect

    Torn, Margaret S.; Harte, John

    2006-02-14

    Historical evidence shows that atmospheric greenhouse gas (GhG) concentrations increase during periods of warming, implying a positive feedback to future climate change. We quantified this feedback for CO2 and CH4 by combining the mathematics of feedback with empirical icecore information and general circulation model (GCM) climate sensitivity, finding that the warming of 1.5-4.5 C associated with anthropogenic doubling of CO2 is amplified to 1.6-6.0 C warming, with the uncertainty range deriving from GCM simulations and paleo temperature records. Thus, anthropogenic emissions result in higher final GhG concentrations, and therefore more warming, than would be predicted in the absence of this feedback. Moreover, a symmetrical uncertainty in any component of feedback, whether positive or negative, produces an asymmetrical distribution of expected temperatures skewed toward higher temperature. For both reasons, the omission of key positive feedbacks and asymmetrical uncertainty from feedbacks, it is likely that the future will be hotter than we think.

  12. Extratropical Influence of Upper Tropospheric Water Vapor on Greenhouse Warming

    NASA Technical Reports Server (NTRS)

    Hu, H.; Liu, W.

    1998-01-01

    The purpose of this paper is to re-examine the impact of upper tropospheric water vapor on greenhouse warming in midlatitudes by analyzing the recent observations of the upper tropospheric water vapor from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS), in conjuction with other space-based measurement and model simulation products.

  13. High-intensity re-warm-ups enhance soccer performance.

    PubMed

    Zois, J; Bishop, D; Fairweather, I; Ball, K; Aughey, R J

    2013-09-01

    The effects of high-intensity, short-duration, re-warm-ups on team-sport-related performance were investigated. In a randomised, cross-over study, participants performed 2×26-min periods of an intermittent activity protocol (IAP) on a non-motorized treadmill, interspersed by 15-min of passive recovery (CON); 3-min small-sided game (SSG); or a 5RM leg-press. Measures included counter-movement jump, repeated-sprint, the Loughborough soccer passing test (LSPT), blood lactate concentration, heart-rate, and perceptual measures. Data were analyzed using effect size (90% confidence intervals), and percentage change; determining magnitudes of effects. A 5RM re-warm-up improved flight-time to contraction-time ratio when compared to SSG (9.8%, ES; 0.5±0.3) and CON (ES: 9.4%, 0.7±0.5) re-warm-ups, remaining higher following the second IAP (8.8%, ES; 0.5±0.3 and 10.2%, ES; 0.6±0.6, respectively). Relative-maximum rate-of-force development was greater in the 5RM condition following the second IAP compared to SSG (29.3%, ES; 0.7±0.5) and CON (16.2%, ES; 0.6±0.6). Repeated-sprint ability during the second IAP improved in the 5RM re-warm-up; peak velocity, mean velocity, and acceleration were 4, 3, and 18% greater, respectively. Within groups, the SSG re-warm-up improved LSPT performance post-intervention; 6.4% (ES: 0.6±0.8) and following the second IAP 6.2% (ES: 0.6±0.6), compared to pre-intervention. A 5RM leg-press re-warm-up improved physical performance, while a SSG re-warm-up enhanced skill execution following standardized intermittent exercise.

  14. When could global warming reach 4°C?

    PubMed

    Betts, Richard A; Collins, Matthew; Hemming, Deborah L; Jones, Chris D; Lowe, Jason A; Sanderson, Michael G

    2011-01-13

    The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) assessed a range of scenarios of future greenhouse-gas emissions without policies to specifically reduce emissions, and concluded that these would lead to an increase in global mean temperatures of between 1.6°C and 6.9°C by the end of the twenty-first century, relative to pre-industrial. While much political attention is focused on the potential for global warming of 2°C relative to pre-industrial, the AR4 projections clearly suggest that much greater levels of warming are possible by the end of the twenty-first century in the absence of mitigation. The centre of the range of AR4-projected global warming was approximately 4°C. The higher end of the projected warming was associated with the higher emissions scenarios and models, which included stronger carbon-cycle feedbacks. The highest emissions scenario considered in the AR4 (scenario A1FI) was not examined with complex general circulation models (GCMs) in the AR4, and similarly the uncertainties in climate-carbon-cycle feedbacks were not included in the main set of GCMs. Consequently, the projections of warming for A1FI and/or with different strengths of carbon-cycle feedbacks are often not included in a wider discussion of the AR4 conclusions. While it is still too early to say whether any particular scenario is being tracked by current emissions, A1FI is considered to be as plausible as other non-mitigation scenarios and cannot be ruled out. (A1FI is a part of the A1 family of scenarios, with 'FI' standing for 'fossil intensive'. This is sometimes erroneously written as A1F1, with number 1 instead of letter I.) This paper presents simulations of climate change with an ensemble of GCMs driven by the A1FI scenario, and also assesses the implications of carbon-cycle feedbacks for the climate-change projections. Using these GCM projections along with simple climate-model projections, including uncertainties in carbon

  15. Atlantic Warm Pool Trigger for the Younger Dryas Climate Event

    NASA Astrophysics Data System (ADS)

    Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.; Teneva, L. T.

    2011-12-01

    There is growing evidence that variability in the size and heat content of the tropical Atlantic Warm Pool impacts circum-North Atlantic climate via the Atlantic Multi-decadal Oscillation mode (Wang et al., 2008). The Atlantic Warm Pool spans the Gulf of Mexico, Caribbean Sea and the western tropical North Atlantic. Barbados is located near the center of the tropical Atlantic Warm Pool and coupled ocean models suggest that Barbados remains near the center of the tropical Atlantic Warm Pool under varying wind stress simulations. Measurements of the oxygen isotope paleothermometer in Acropora palmata coral species recovered from cores offshore Barbados, show a 3oC monotonic decrease in sea surface temperature from 13106 ± 83 to 12744 ± 61 years before present (errors given as 2 sigma). This interval corresponds to a sea level rise from 71.4 meters to 67.1 meters below present levels at Barbados. The 3oC temperature decrease is captured in eight A. palmata specimens that are in stratigraphic sequence, 230Th/234U dated, and analyzed for oxygen isotopes. All measurements are replicated. We are confident that this is the warm pool equivalent of the Younger Dryas climate event. The initiation of this temperature drop in the Atlantic Warm Pool predates the Younger Dryas start in Greenland ice cores, reported to start at 12896 ± 138 years (relative to AD 2000) (Rasmussen et al., 2006), while few other Younger Dryas climate records are dated with similar accuracy to make the comparison. Rasmussen, S.O., Andersen, K.K., Svensson, A.M., Steffensen, J.P., Vinther, B.M., Clausen, H.B., Siggaard-Andersen, M.L., Johnsen, S.J., Larsen, L.B., Dahl-Jensen, D., Bigler, M., Röthlisberger, R., Fischer, H., Goto-Azuma, K., Hansson, M.E., and Ruth, U., 2006, A new Greenland ice core chronology for the last glacial termination: J. Geophys. Res., v. 111, p. D06102. Wang, C., Lee, S.-K., and Enfield, D.B., 2008, Atlantic Warm Pool acting as a link between Atlantic Multidecadal

  16. The Effects of Local Warming on Surgical Site Infection

    PubMed Central

    Dellinger, E. Patchen; Weber, James; Swenson, Ron Edward; Kent, Christopher D.; Swanson, Paul E.; Harmon, Kurt; Perrin, Margot

    2015-01-01

    Abstract Background: Surgical site infections (SSI) account for a major proportion of hospital-acquired infections. They are associated with longer hospital stay, readmissions, increased costs, mortality, and morbidity. Reducing SSI is a goal of the Surgical Care Improvement Project and identifying interventions that reduce SSI effectively is of interest. In a single-blinded randomized controlled trial (RCT) we evaluated the effect of localized warming applied to surgical incisions on SSI development and selected cellular (immune, endothelial) and tissue responses (oxygenation, collagen). Methods: After Institutional Review Board approval and consent, patients having open bariatric, colon, or gynecologic-oncologic related operations were enrolled and randomly assigned to local incision warming (6 post-operative treatments) or non-warming. A prototype surgical bandage was used for all patients. The study protocol included intra-operative warming to maintain core temperature ≥36°C and administration of 0.80 FIO2. Patients were followed for 6 wks for the primary outcome of SSI determined by U.S. Centers for Disease Control (CDC) criteria and ASEPSIS scores (additional treatment; presence of serous discharge, erythema, purulent exudate, and separation of the deep tissues; isolation of bacteria; and duration of inpatient stay). Tissue oxygen (PscO2) and samples for cellular analyses were obtained using subcutaneous polytetrafluoroethylene (ePTFE) tubes and oxygen micro-electrodes implanted adjacent to the incision. Cellular and tissue ePTFE samples were evaluated using flow cytometry, immunohistochemistry, and Sircol™ collagen assay (Biocolor Ltd., Carrickfergus, United Kingdom). Results: One hundred forty-six patients participated (n=73 per group). Study groups were similar on demographic parameters and for intra-operative management factors. The CDC defined rate of SSI was 18%; occurrence of SSI between groups did not differ (p=0.27). At 2 wks, warmed

  17. Tracing ram-pressure stripping with warm molecular hydrogen emission

    SciTech Connect

    Sivanandam, Suresh; Rieke, Marcia J.; Rieke, George H.

    2014-12-01

    We use the Spitzer Infrared Spectrograph to study four infalling cluster galaxies with signatures of ongoing ram-pressure stripping. H{sub 2} emission is detected in all four, and two show extraplanar H{sub 2} emission. The emission usually has a warm (T ∼ 115-160 K) and a hot (T ∼ 400-600 K) component that is approximately two orders of magnitude less massive than the warm one. The warm component column densities are typically 10{sup 19} to 10{sup 20} cm{sup –2} with masses of 10{sup 6} to 10{sup 8} M {sub ☉}. The warm H{sub 2} is anomalously bright compared with normal star-forming galaxies and therefore may be excited by ram-pressure. In the case of CGCG 97-073, the H{sub 2} is offset from the majority of star formation along the direction of the galaxy's motion in the cluster, suggesting that it is forming in the ram-pressure wake of the galaxy. Another galaxy, NGC 4522, exhibits a warm H{sub 2} tail approximately 4 kpc in length. These results support the hypothesis that H{sub 2} within these galaxies is shock-heated from the interaction with the intracluster medium. Stripping of dust is also a common feature of the galaxies. For NGC 4522, where the distribution of dust at 8 μm is well resolved, knots and ripples demonstrate the turbulent nature of the stripping process. The Hα and 24 μm luminosities show that most of the galaxies have star-formation rates comparable to similar mass counterparts in the field. Finally, we suggest a possible evolutionary sequence primarily related to the strength of ram-pressure that a galaxy experiences to explain the varied results observed in our sample.

  18. King penguin population threatened by Southern Ocean warming

    PubMed Central

    Le Bohec, Céline; Durant, Joël M.; Gauthier-Clerc, Michel; Stenseth, Nils C.; Park, Young-Hyang; Pradel, Roger; Grémillet, David; Gendner, Jean-Paul; Le Maho, Yvon

    2008-01-01

    Seabirds are sensitive indicators of changes in marine ecosystems and might integrate and/or amplify the effects of climate forcing on lower levels in food chains. Current knowledge on the impact of climate changes on penguins is primarily based on Antarctic birds identified by using flipper bands. Although flipper bands have helped to answer many questions about penguin biology, they were shown in some penguin species to have a detrimental effect. Here, we present for a Subantarctic species, king penguin (Aptenodytes patagonicus), reliable results on the effect of climate on survival and breeding based on unbanded birds but instead marked by subcutaneous electronic tags. We show that warm events negatively affect both breeding success and adult survival of this seabird. However, the observed effect is complex because it affects penguins at several spatio/temporal levels. Breeding reveals an immediate response to forcing during warm phases of El Niño Southern Oscillation affecting food availability close to the colony. Conversely, adult survival decreases with a remote sea-surface temperature forcing (i.e., a 2-year lag warming taking place at the northern boundary of pack ice, their winter foraging place). We suggest that this time lag may be explained by the delay between the recruitment and abundance of their prey, adjusted to the particular 1-year breeding cycle of the king penguin. The derived population dynamic model suggests a 9% decline in adult survival for a 0.26°C warming. Our findings suggest that king penguin populations are at heavy extinction risk under the current global warming predictions. PMID:18268328

  19. King penguin population threatened by Southern Ocean warming.

    PubMed

    Le Bohec, Céline; Durant, Joël M; Gauthier-Clerc, Michel; Stenseth, Nils C; Park, Young-Hyang; Pradel, Roger; Grémillet, David; Gendner, Jean-Paul; Le Maho, Yvon

    2008-02-19

    Seabirds are sensitive indicators of changes in marine ecosystems and might integrate and/or amplify the effects of climate forcing on lower levels in food chains. Current knowledge on the impact of climate changes on penguins is primarily based on Antarctic birds identified by using flipper bands. Although flipper bands have helped to answer many questions about penguin biology, they were shown in some penguin species to have a detrimental effect. Here, we present for a Subantarctic species, king penguin (Aptenodytes patagonicus), reliable results on the effect of climate on survival and breeding based on unbanded birds but instead marked by subcutaneous electronic tags. We show that warm events negatively affect both breeding success and adult survival of this seabird. However, the observed effect is complex because it affects penguins at several spatio/temporal levels. Breeding reveals an immediate response to forcing during warm phases of El Niño Southern Oscillation affecting food availability close to the colony. Conversely, adult survival decreases with a remote sea-surface temperature forcing (i.e., a 2-year lag warming taking place at the northern boundary of pack ice, their winter foraging place). We suggest that this time lag may be explained by the delay between the recruitment and abundance of their prey, adjusted to the particular 1-year breeding cycle of the king penguin. The derived population dynamic model suggests a 9% decline in adult survival for a 0.26 degrees C warming. Our findings suggest that king penguin populations are at heavy extinction risk under the current global warming predictions. PMID:18268328

  20. Vascular plants promote ancient peatland carbon loss with climate warming.

    PubMed

    Walker, Tom N; Garnett, Mark H; Ward, Susan E; Oakley, Simon; Bardgett, Richard D; Ostle, Nicholas J

    2016-05-01

    Northern peatlands have accumulated one third of the Earth's soil carbon stock since the last Ice Age. Rapid warming across northern biomes threatens to accelerate rates of peatland ecosystem respiration. Despite compensatory increases in net primary production, greater ecosystem respiration could signal the release of ancient, century- to millennia-old carbon from the peatland organic matter stock. Warming has already been shown to promote ancient peatland carbon release, but, despite the key role of vegetation in carbon dynamics, little is known about how plants influence the source of peatland ecosystem respiration. Here, we address this issue using in situ (14)C measurements of ecosystem respiration on an established peatland warming and vegetation manipulation experiment. Results show that warming of approximately 1 °C promotes respiration of ancient peatland carbon (up to 2100 years old) when dwarf-shrubs or graminoids are present, an effect not observed when only bryophytes are present. We demonstrate that warming likely promotes ancient peatland carbon release via its control over organic inputs from vascular plants. Our findings suggest that dwarf-shrubs and graminoids prime microbial decomposition of previously 'locked-up' organic matter from potentially deep in the peat profile, facilitating liberation of ancient carbon as CO2. Furthermore, such plant-induced peat respiration could contribute up to 40% of ecosystem CO2 emissions. If consistent across other subarctic and arctic ecosystems, this represents a considerable fraction of ecosystem respiration that is currently not acknowledged by global carbon cycle models. Ultimately, greater contribution of ancient carbon to ecosystem respiration may signal the loss of a previously stable peatland carbon pool, creating potential feedbacks to future climate change.