<div><strong><a href="http://www.nasa.gov/topics/earth/agu2007_press.html">http://www.nasa.gov/topics/earth/agu2007_press.html</a></strong></div>
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<div><strong>EARTH'S "TIPPING POINTS": HOW CLOSE ARE WE?<br>TIME:</strong> Thurs., Dec. 13, 12 noon EST (9 a.m. PST)<br><b>RELATED SESSION:</b> GC44A<br>Abrupt changes in climate are now an established phenomenon in Earth's history and there is growing concern that our planet may be at a "tipping point" of dramatic climate change due this time to anthropogenic influences. Scientists from across different disciplines are now looking at many parts of the Earth system for signs of such pivotal shifts either already underway or likely to happen in this century. Researchers will present the latest results from the perspective of global climate as well as potential impacts on three key regions of the globe. James Hansen discusses the "unrealized" global warming of Earth's climate system and the resulting need for urgent action to cut emissions beyond carbon dioxide. Richard Alley discusses the possibility that sustained warming of a few decades could produce major ice sheet losses that would last centuries. Peter Webster reports on a societal tipping point along three heavily populated Asian river basins when climate-induced changes to river flows collide with population growth. Joey Comiso reports that this year's large Arctic sea ice decline may be the tipping point for perennial ice and a recovery may not be possible in the foreseeable future.<br>
Panelists:<br> </div>
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<li>James Hansen, director, NASA Goddard Institute for Space Studies,; adjunct professor of earth and environmental sciences, Columbia University, New York<br>
<li>Peter Webster, professor, School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta<br>
<li>Joey Comiso, senior research scientist for polar oceanography, NASA Goddard Space Flight Center, Greenbelt, Md.<br>Richard Alley, Evan Pugh professor of geosciences, associate of the Earth and Environmental Systems Institute, Pennsylvania State University, State College, Pa.</li>
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<div>Global Warming "Tipping Points" Reached, Scientist Says:</div>
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<div><a href="http://news.nationalgeographic.com/news/2007/12/071214-tipping-points.html">http://news.nationalgeographic.com/news/2007/12/071214-tipping-points.html</a></div>
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<div>------------------------------------------</div><br>Vision2020 Post: Ted Moffett