New search for global warming at poles

Earth's coldest regions are vital heat sinks and, eventually, hold the key to future rises in sea levels.

By Peter N. Spotts | Staff writer of The Christian Science Monitor

from the February 26, 2007 edition

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For the next two years, the coldest places on Earth will become some of the hottest laboratories in the history of modern science.

This Thursday marks the official start of the International Polar Year (IPY), an unprecedented research assault on Antarctica and the Arctic.

Some 10,000 scientists from more than 60 countries launched the push because of significant changes they see taking place at these frozen ends of the Earth. Many hold that global warming is triggering these changes, including shrinking sea ice in the Arctic Ocean, thawing permafrost, and growing instability in Greenland's ice cap and in some floes coursing through Antarctica's ice cap.

The US kicks off its part of the $1.5-billion project with opening ceremonies Tuesday in Washington.

The goal is to gain a deeper understanding of processes affecting everything from the flow of glaciers, and key features of polar climate to plankton and polar bears. In addition, researchers plan to leave a legacy of networked, standard sensors and buoys that will help track changes in these crucial regions long after the IPY ends.

Why North and South poles matter

At first glance, the poles may seem too remote to matter to anyone who doesn't live there. But Earth's "cryosphere" – its high-latitude regions of snow and ice – represents a central piece of the climate system. The poles act as sinks for the heat generated in the tropics and carried toward higher latitudes by the oceans and atmosphere. Over many centuries, the ice caps on Greenland and Antarctica hold the key to future sea-level rise as the climate warms up north.

Thus, the hidden hand of a changing Arctic reaches farther south than icebergs alone suggest.

"There is no magic curtain that drops down at 60 degrees north," says ice scientist Jacqueline Richter-Menge, who heads climate-related research at the US Army Corps of Engineers' Cold Regions Research and Engineering Laboratory in Hanover, N.H.

Changes in ecosystems

For instance, ecosystems stretching from the Labrador Sea to the continental shelf off North Carolina are changing because colder, less-salty water is flowing along the continental shelf from the Arctic Ocean into the northwest Atlantic, according to two Cornell University scientists. Many researchers attribute the Arctic Ocean's freshening to global warming.

The scientists note that while overfishing triggered the collapse of lucrative cod fishing off the Canadian Maritime Provinces, this fresher, colder water along the shelf has hindered the cod's recovery there compared with stocks farther south.

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