Saturday, 9 May 2009

Is Global warming just delaying a new Ice Age ?

Maybe the causes of global warming are not as recent as the industrial coal-fueled revolution 200 years ago, but as old as thousands of years ago with intensive agriculture and large scale deforestation. That´s what recent studies show: following a pattern of alterning warm and cold periods, such as have occurred at regular 100 000-year intervals during the last million years, the world should presently be living a new cold era! Only the cumulative effects of thousands of years of human activity are preventing the world from entering a new glacial age.

Stephen Vavrus and colleague John Kutzbach , climatologists at the University of Wisconsin-Madison's Center for Climatic Research and the Nelson Institute for Environmental Studies, provided detailed evidence in support of an idea first put forward by climatologist William F. Ruddiman of the University of Virginia.

"We're at a very favorable state right now for increased glaciation," says Kutzbach. "Nature is favoring it at this time in orbital cycles, and if humans weren't in the picture it would probably be happening today."

Using three different climate models and removing the amount of greenhouse gases humans have injected into the atmosphere during the past 5,000 to 8,000 years, Vavrus and Kutzbach observed more permanent snow and ice cover in regions of Canada, Siberia, Greenland and the Rocky Mountains .

Source: ScienceDaily