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.

from the February 26, 2007 edition

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In their place, marine life, including shrimp and snow crab, that cod would have eaten are flourishing. The changes in water conditions have altered the timing for peak production among tiny plankton that nourish creatures higher up the food chain.

"These timing changes are going to lead to changes in the ecosystem. There will be winners and losers in the ecosystem. And there will be winners and losers in society," says Charles Greene, a Cornell oceanographer who was a co-author of the report.

Meanwhile, in the south, scientists working on the global Census of Marine Life say they see biologically significant shifts in marine life along the sea floor that once anchored two large ice shelves known as Larson A and B. They broke away from the Antarctic Peninsula over the past 12 years.

"The more we understand what's going on, the more winners there will be," Dr. Greene says.

International grass-roots effort

The IPY coincides with the 50th anniversary of the International Geophysical Year (IGY), the first postwar effort to study the entire planet, from the deep-sea floor and below to the outermost reaches of the atmosphere. Although this year's effort is dubbed the polar year, it spans two years to allow scientists to track conditions at both poles through a complete summer-winter-summer cycle.

The IPY includes more biology and ecology to better gauge the effect changes are having on plants and animals, as well as on the organic carbon stored in frozen tundra. Scientists say that as the Arctic in particular warms, they expect this carbon to reach the atmosphere as carbon dioxide and methane – turning the Great White North into a source of heat-trapping greenhouse gases.

Unlike the IGY, "this is a very grass-roots effort," says Robin Bell, a senior scientist at the Lamont-Doherty Earth Observatory in Palisades, N.Y.

Last week, Dr. Bell and colleagues described how lakes in the right location beneath Antarctic ice "rivers" accelerate the ice's movement toward the sea.

The poles "are the parts of the planet changing most rapidly" with global warming, she says. Understanding them is key to understanding how the rest of the planet is likely to respond.

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