Getting Warmer? Prehistoric Climate Can Help Forecast Future ChangesNovember 25, 2008The first comprehensive reconstruction of an extreme warm period shows the sensitivity of the climate system to changes in carbon dioxide (CO2) levels as well as the strong influence of ocean temperatures, heat transport from equatorial regions, and greenhouse gases on Earth's temperature. New data allow for more accurate predictions of future climate and improved understanding of today's warming. Past warm periods provide real data on climate change and are natural laboratories for understanding the global climate system. Scientists examined fossils from 3.3 to 3.0 million years ago, known as the mid-Pliocene warm period. Research was conducted by the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) group, led by the U.S. Geological Survey.
"PRISM's research provides objective, unbiased data for climate modelers to better understand the environment in which we live and for decision makers to make informed adaptation and mitigation strategies that yield the greatest benefits to society and the environment," said Senior Advisor to USGS Global Change Programs Thomas Armstrong. "This is the most comprehensive global reconstruction for any warm period and emphasizes the importance of examining the past state of Earth's climate system to understand the future." The mid-Pliocene experienced the most extreme warming over the past 3.3 million years. Global average temperatures were 2.5°C (4.5°F) greater than today and within the range projected for the 21st century by the Intergovernmental Panel on Climate Change. "Exploring the mid-Pliocene will further understanding on the role of ocean circulation in a warming world, the impacts of altered storm tracks, polar versus tropical sensitivity, and the impacts of altered atmospheric CO2 and oceanic energy transport systems," said USGS scientist Harry Dowsett, also lead scientist for PRISM. "We used fossils dated to the mid-Pliocene to reconstruct sea surface and deepwater ocean temperatures, and will continue research by studying specific geographic areas, vegetation, sea ice extent and other environmental characteristics during the Pliocene." Since CO2 levels during the mid-Pliocene were only slightly higher than today's levels, PRISM research suggests that a slight increase in our current CO2 level could have a large impact on temperature change. Research also shows warming of as much as 18°C, bringing temperatures from -2°C to 16°C, in the high latitudes of the North Atlantic and Arctic Oceans during the mid-Pliocene. Warming in the Pacific, similar to a present day El Niño, was a characteristic of the mid-Pliocene. Global sea surface and deep water temperatures were found to be warmer than those of today, impacting the ocean's circulation system and climate. Data suggest the likely cause of mid-Pliocene warmth was a combination of several factors, including increased heat transport from equatorial regions to the poles and increased greenhouse gases. PRISM has been chosen by the Pliocene Model Intercomparison Project of Paleoclimate Modelling Intercomparison Project Phase II as the dataset against which to run and test the performance of climate models for the Pliocene. PRISM's primary collaborators are Columbia University, Duke University, the University of Leeds and the British Antarctic Survey. For a podcast interview with USGS scientists Harry Dowsett and Marci Robinson on this research, listen to Episode 77 of USGS CoreCast at http://www.usgs.gov/corecast/. For more information and to view the compiled data, visit http://geology.er.usgs.gov/eespteam/prism/index.html. U.S. Geological Survey Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. Chest Pain Visual System Antidepressants Chimpanzees Heart Surgery Butterflies Sleep Problems Circadian Clock Cancer Screening Circadian Rhythms Neanderthal Microscopy Antipsychotic Bacteria Greenhouse Gas Arctic sea ice Child Care Neuroticism Atomic Clock Extrasolar Planets Bisphosphonates Epilepsy Angioplasty Meningitis Motor Neurons
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Related Climate System Current Events and Climate System News Articles World's largest aerosol sensing network has leafy origins Twenty years ago, Brent Holben was part of a NASA team studying vegetation from space. In an unlikely career twist, his research morphed into the study of a critical, if overlooked, subplot in the story of climate change. Close relationship between past warming and sea-level rise In a paper in Nature Geoscience, a team from the National Oceanography Centre, Southampton (NOCS), along with colleagues from Tübingen (Germany) and Bristol presents a novel continuous reconstruction of sea level fluctuations over the last 520 thousand years. Global sunscreen won't save corals Emergency plans to counteract global warming by artificially shading the Earth from incoming sunlight might lower the planet's temperature a few degrees, but such "geoengineering" solutions would do little to stop the acidification of the world oceans that threatens coral reefs and other marine life. Melting Greenland Ice Sheets May Threaten Northeast United States, Canada Melting of the Greenland ice sheet this century may drive more water than previously thought toward the already threatened coastlines of New York, Boston, Halifax, and other cities in the northeastern United States and Canada. A global responsibility to help vulnerable communities adapt For one international community - the 165,000 strong Inuit community dispersed across the Arctic coastline in small, remote coastal settlements in Alaska, Canada, Greenland and Siberia - it is already too late to prevent some of the negative effects of climate change. Climate change odds much worse than thought The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth's climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago - and could be even worse than that. Global monsoon drives long-term carbon cycles in the ocean Monsoon is a global system, and many arrays of evidence indicate that it drives long-term cyclicity of the carbon reservoir in the global ocean. Fire is important part of global climate change, report scientists Fire must be accounted for as an integral part of climate change, according to 22 authors of an article published in the April 24 issue of the journal Science. The authors determined that intentional deforestation fires alone contribute up to one-fifth of the human-caused increase in emissions of carbon dioxide, a heat-trapping gas that raises global temperature. Critical turning point can trigger abrupt climate change Ice ages are the greatest natural climate changes in recent geological times. Their rise and fall are caused by slight changes in the Earth's orbit around the Sun due to the influence of the other planets. Global Warming: Cuts in Greenhouse Gas Emissions Would Save Arctic Ice, Reduce Sea Level Rise The threat of global warming can still be greatly diminished if nations cut emissions of heat-trapping greenhouse gases by 70 percent this century, according to a new analysis. More Climate System Current Events and Climate System News Articles |
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