November 12, 2008
Researchers Predict Massive Freeze In 10,000 Years
Scientists reported Wednesday that in 10,000 years a massive, worldwide freeze could overcome the planet, more deadly than the Ice Age.
British and Canadian researchers said greenhouse gases could prove beneficial in the future to battle a chill that could cover Canada and the United States, Europe and Russia in permanent ice.
However, scientists contend the world should not stop fighting global warming, theoretically stoked by human emissions of heat-trapping gases from burning fossil fuels.
The research was based on records of tiny marine fossils and the earth's shifting orbit.
"We're saying: 'don't push the panic button'," said Thomas Crowley, an American scientist at Edinburgh University, who co-authored the study.
The findings were published in the journal Nature.
"There's no excuse for saying 'we've got to keep pumping carbon dioxide (CO2) into the atmosphere,'" he said.
Scientists predict the cooling will begin in 10,000 to 100,000 years.
"Geologically it's tomorrow," he said. "But we have a lot of time to argue about the appropriate level of greenhouse gases."
In the last Ice Age, sea levels fell about 130 meters and much of Russia escaped a big ice sheet.
Scientists can build sea level records from fossils because salt is more concentrated when there is less sea water.
"Presumably, future society could prevent this transition indefinitely with very modest adjustments to the atmospheric CO2 level," they wrote.
Experts believe a shift to a bigger blanket of ice would mark the end of a period of warming that began 50 million years ago, when Antarctica was almost ice-free.
Scientists said the recent changes between Ice Ages and warmer periods over the past 900,000 years are growing more dramatic.
A similar freezing shift happened more than 34 million years ago when Antarctica was first covered by ice.
Scientists say cooling could be accelerated by a small growth of polar ice sheets, with ice and snow reflecting more of the sun's heat back into space.
"Historians of science hate to say 'this is a special time'," Crowley said.
"But when you go through the models, each step seems reasonable and you get to an astonishing conclusion that we are right at the end of a 50-million-year evolution."
Researchers say more analysis is needed of this alarming finding.
"It might not come for tens of thousands of years," he said. "I'm sure some headline writers will want to say 'CO2 good for the atmosphere', or 'CO2 is good for us'. That's not the case."
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