Glaciers of the world synchronized

By | September 27, 2009

Glaciers of the world synchronized

Results of a new study add evidence that climate swings in the northern hemisphere over the past 12,000 years have been tightly linked to changes in the tropics.

The findings, published this week in the journal Science, suggest that a prolonged cold spell that caused glaciers in Europe and North America to creep forward several hundred years ago may have affected climate patterns as far south as Peru, causing tropical glaciers there to expand, too. …

Most of the world’s glaciers are now retreating, as manmade greenhouse gas levels rise.

The Intergovernmental Panel on Climate Change predicts that global temperatures may climb another 1.1 to 6.4 degrees Celsius by this century’s end.

“If the current dramatic warming projections are correct, we have to face the possibility that the glaciers may soon disappear,” said Joerg Schaefer, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory (LDEO) and co-author of the paper.

In a warmer world, regions that depend on glaciers for drinking water, farming and hydropower will need to come up with strategies to adapt….

Human civilization arose during fairly stable temperatures since the end of the last ice age, about 12,000 years ago. But research shows that even during this time glaciers fluctuated in large and sometimes surprising ways.

Most of the world’s glaciers are now retreating, as manmade greenhouse gas levels rise.

The Intergovernmental Panel on Climate Change predicts that global temperatures may climb another 1.1 to 6.4 degrees Celsius by this century’s end.

“If the current dramatic warming projections are correct, we have to face the possibility that the glaciers may soon disappear,” said Joerg Schaefer, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory (LDEO) and co-author of the paper.

In a warmer world, regions that depend on glaciers for drinking water, farming and hydropower will need to come up with strategies to adapt.

Recent developments in a technique called surface exposure dating have allowed scientists to place far more precise dates on glacial fluctuations during recent times than was previously possible.

When glaciers advance, they drag rocks and dirt with them. When they recede, ridges of debris called moraines are left behind, and the newly exposed deposits are bombarded by cosmic rays passing through Earth’s atmosphere.

The rays react with the rock and over time form tiny amounts of the rare chemical isotope beryllium-10. By measuring the buildup of this isotope in glacial rocks, scientists can calculate when the glaciers receded.

Using this technique, the authors showed that glaciers in southern Peru moved at times similar to those in the northern hemisphere.

– via Eureka Alert

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