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Scientists Study 'Snowball Earth'
UPI Correspondent Victoria (UPI) Nov 28, 2006 Canadian scientists have determined the factors involved in ending a severe ice age 750 million years ago that nearly completely froze Earth's oceans. Since the factors initiating a so-called "Snowball Earth" era have been the subject of much study, Jeffrey Lewis and colleagues at the University of Victoria focused on determining the factors that pulled Earth from its snowball state. Noting that accepted values for both snow and ice albedo -- the ratio of incident to reflected solar radiation -- cover a wide range, the researchers sought to quantify the relative sensitivity of various surface albedos on the same climate model as it emerges from a snowball state. They found the range of ice, snow, and land albedos and the resulting minimum carbon dioxide greenhouse forcing required for deglaciation of the Neoproterozoic snowball Earth. They also found greenhouse forcing can vary by nearly an order of magnitude within the accepted albedo ranges, suggesting the physics of deglaciation in terms of radiation budgets, snow and ice dynamics, and atmospheric processes needs to be better modeled. The study is detailed in the journal Geophysical Research Letters.
Source: United Press International Community Email This Article Comment On This Article Related Links University of Victoria Beyond the Ice Age
Study Shows Growing Role Of Asia As Source Of Arctic Pollution
Helsinki (AFP) Nov 16, 2006Europe has succeeded in reducing toxic emissions that pollute the Arctic, but Asia is playing an increasing role in damaging the environmentally-sensitive region, the Arctic Council said in a study published on Thursday. Over the past 15 years, "the reduction of emissions in Europe has had a cleaning effect on the Arctic," the Arctic Monitoring and Assessment Programme (AMAP) said in its report. |
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