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Warming Climate will not cause an Ice Age
| Recent news articles speculate that a warmer climate in the Arctic may eventually lead to a big chill in Europe or North America, or even a new Ice Age. The new movie The Day after Tomorrow dramatizes this concern. The speculation is that melting of ice and greater flow of fresh water into the Arctic Ocean may shut down the overturning of deep and shallow water in the North Atlantic Ocean (see Climate Science Forum, summer 2002). That would stop the flow of the Gulf Stream which delivers warm water to Europe. Cooling in Europe would allow glaciers to gradually grow, until finally a new ice sheet forms - so the speculation goes. What do climate scientists say about such a chain of possibilities? “It is safe to say that global warming will not lead to the onset of a new ice age,” conclude two Canadian scientists, Andrew Weaver and Claude Hillaire-Marcel, in a recent article in Science 1.
The Canadians found evidence of North Atlantic shutdowns only at the peak of the last ice age and during some short, very cold intervals. But they found no evidence at all during the warm phases between ice ages, known as “interglacials.” Weaver and Hillaire-Marcel also looked for evidence that the Atlantic Ocean circulation might have been changed when a massive lake of glacial melt water in Canada, known as “Lake Ojibway”, suddenly spilled into the sea 8200 years ago. They found no sign that the massive flow of fresh water affected the Atlantic's circulation then. Click to continue . . . ______ |
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