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| 5/25 |
| 2005/2/18-19 [Science/GlobalWarming] UID:36230 Activity:nil |
2/18 Concrete evidence of human role in global warming from Scripps
Institute.
http://www.timesonline.co.uk/printFriendly/0,,1-3-1489955-3,00.html
http://scrippsnews.ucsd.edu/print_article.cfm?article_num=666
You may now commence the flame war.
\_ Why do you hate America? |
| 5/25 |
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| www.timesonline.co.uk/printFriendly/0,,1-3-1489955-3,00.html CLOSE WINDOW February 18, 2005 Scientists say they have found proof that man-made emissions have caused global warming (MANAN VATSYAYANA/AFP/Getty Images) New proof that man has caused global warming From Mark Henderson, Science Correspondent, in Washington The strongest evidence yet that global warming has been triggered by huma n activity has emerged from a major study of rising temperatures in the worlds oceans. The results are so compelling that they should end controversy about the causes of climate change, one of the scientists who led the study said y esterday. "The debate about whether there is a global warming signal now is over, a t least for rational people," said Tim Barnett, of the Scripps Instituti on of Oceanography in La Jolla, California. If a politician stands up and says the uncertainty is too great to believe these models, that is no longer tenable." In the study, Dr Barnetts team examined more than seven million observat ions of temperature, salinity and other variables in the worlds oceans, collected by the US National Oceanic and Atmospheric Administration, an d compared the patterns with those that are predicted by computer models of various potential causes of climate change. It found that natural variation in the Earths climate, or changes in sol ar activity or volcanic eruptions, which have been suggested as alternat ive explanations for rising temperatures, could not explain the data col lected in the real world. Models based on man-made emissions of greenhou se gases, however, matched the observations almost precisely. "What absolutely nailed it was the greenhouse model," Dr Barnett told the American Association for the Advancement of Science conference in Washi ngton. Two models, one designed in Britain and one here in the US, got i t almost exactly. Climate change has affected the seas in different ways in different parts of the world: in the Atlantic, for example, rising temperatures can be observed up to 700 metres below the surface, while in the Pacific the wa rming is seen only up to 100m down. Only the greenhouse models replicated the changes that have been observed in practice. "The fact that this has gone on in different ways gives us the chance to figure out who did it," Dr Barnett said. "All the potential culprits have been ruled out except one. "This is perhaps the most compelling evidence yet that global warming is happening right now, and it shows that we can successfully simulate its past and its likely future evolution. The statistical significance of th ese results is far too strong to be merely dismissed and should wipe out much of the uncertainty about the reality of global warming." Dr Barnett said the results, which are about to be submitted for publicat ion in a major peer-reviewed journal, should put further pressure on the Bush Administration to sign up to the Kyoto Protocol, which came into f orce on Wednesday. "It is now time for nations that are not part of Kyot o to reevaluate and see if it would be to their advantage to join," he s aid. The debate is not have we got a clear global warming signal, the debate is what we are going to do ab out it." In a separate study, also presented to the conference, a team led by Ruth Curry of Woods Hole Oceanographic Institution in Connecticut has establ ished that 20,000 square kilometres of freshwater ice melted in the Arct ic between 1965 and 1995. Further melting on this scale could be sufficient to turn off the ocean c urrents that drive the Gulf Stream, which keeps Britain up to 6C warmer than it would otherwise be. "It is taking the first steps, the system is moving in that direction," Dr Curry said. "The new ocean study, taken together with the numberous validations of th e same models in the atmosphere, portends far broader changes. Other par ts of the world will face similar problems to those expected, and being observed now, in the western US. "The skill demonstrated by the climate models in handling the changing pl anetary heat budget suggests that these scenarios have a high enough pro bability of actually happening that they need to be taken seriously by d ecision-makers." |
| scrippsnews.ucsd.edu/print_article.cfm?article_num=666 edu For Release: February 17, 2005 Scripps Researchers Find Clear Evidence of Human-Produced Warming in Worl d's Oceans Climate warming likely to impact water resources in regions around the gl obe Scientists at Scripps Institution of Oceanography at the University of Ca lifornia, San Diego, and their colleagues have produced the first clear evidence of human-produced warming in the world's oceans, a finding they say removes much of the uncertainty associated with debates about globa l warming. In a new study conducted with colleagues at Lawrence Livermore National L aboratory's Program for Climate Model Diagnosis and Intercomparison (PCM DI), Tim Barnett and David Pierce of Scripps Institution used a combination of computer models and real-world "observed" data to capture signals of th e penetration of greenhouse gas-influenced warming in the oceans. The au thors make the case that their results clearly indicate that the warming is produced anthropogenically, or by human activities. "This is perhaps the most compelling evidence yet that global warming is happening right now and it shows that we can successfully simulate its p ast and likely future evolution," said Tim Barnett, a research marine ph ysicist in the Climate Research Division at Scripps. Barnett says he was "stunned" by the results because the computer models reproduced the pen etration of the warming signal in all the oceans. "The statistical signi ficance of these results is far too strong to be merely dismissed and sh ould wipe out much of the uncertainty about the reality of global warmin g" border= At a news briefing (Feb. According to Barnett, the climate mechanisms behind the ocean study will produce broad-scale changes across the atmosphere and land. In the decad es immediately ahead, the changes will be felt in regional water supplie s, including areas impacted by accelerated glacier melting in the South American Andes and in western China, putting millions of people at risk without adequate summertime water. Similarly, recent research by Barnett and his colleagues with the Acceler ated Climate Prediction Initiative analyzed climate warming impacts on t he western United States using one of the models involved in the new stu dy. The earlier study concluded that climate warming will likely alter w estern snow pack resources and the region's hydrological cycle, posing a water crisis in the western US within 20 years. "The new ocean study, taken together with the numerous validations of the same models in the atmosphere, portends far broader changes," said Barn ett. "Other parts of the world will face similar problems to those expec ted--and being observed now--in the western US The skill demonstrated by the climate models in handling the changing planetary heat budget sug gests that these scenarios have a high enough probability of actually ha ppening that they need to be taken seriously by decision makers." border= In the new study, Barnett and his colleagues used computer models of climate to calculate human-produced warming over the last 40 years i n the world's oceans. In all of the ocean basins, the warming signal fou nd in the upper 700 meters predicted by the models corresponded to the m easurements obtained at sea with confidence exceeding 95 percent. The co rrespondence was especially strong in the upper 500 meters of the water column. It is this high degree of visual agreement and statistical significance t hat leads Barnett to conclude that the warming is the product of human i nfluence. Efforts to explain the ocean changes through naturally occurri ng variations in the climate or external forces- such as solar or volcan ic factors--did not come close to reproducing the observed warming. In addition to Barnett and Pierce, coauthors of the study include Krishna Achutarao, Peter Gleckler and Benjamin Santer of Lawrence Livermore Nat ional Laboratory. The global climate models used in the study included the Parallel Climate Model from the National Center for Atmospheric Research and Department of Energy (DOE) and the HadCM3 from the Hadley Centre (United Kingdom). The sharing of these model results made this study possible, says Barnet t The work was a contribution on behalf of the International Detection and Attribution Group (IDAG), which is sponsored by the National Oceanic and Atmospheric Administration's (NOAA) Climate Change Data Detection P rogram, a jointly funded NOAA and DOE program. Additional support was pr ovided by DOE through support of PCMDI and Scripps. |