WASHINGTON—It seems like a paradox, but scientists say the best places to study global warming are the coldest regions on Earth. The Arctic, the Antarctic and lofty mountain ranges are showing the impact of higher temperatures more rapidly and dramatically than anywhere else on the planet.
Collapsing ice sheets, thawing permafrost, shrinking glaciers and thinning sea ice will be the focus of a yearlong, worldwide scientific extravaganza known as the International Polar Year, which researchers and policymakers from 60 nations will formally launch in Paris on Thursday after five years of preparations.
"This is a critical time in humanity's relationship with our planet," said an author of the IPY concept, Robert Bindschadler, an Antarctic scientist who's based at NASA's Goddard Space Flight Center in Greenbelt, Md.
"What's happening in the polar regions is a powerful, irrefutable demonstration of change on a global scale," he said at a pre-launch ceremony in Washington.
"The poles are changing even faster than we anticipated," said Robin Bell, the head of the Polar Research Board at the National Academy of Sciences. "We need to monitor environmental change to understand what's happening to our planet."
Data collected for the IPY will provide a baseline by which to measure future climate changes, according to Arden Bement, the director of the National Science Foundation.
"We want to ring the Arctic with scientific observatories," said Conrad Lautenbacher, the administrator for the National Oceanic and Atmospheric Administration.
Warming is felt most sharply in the far north, where temperatures are rising twice as fast as the global average.
Greenland, for example, lost as much ice in one year as is contained in all the Swiss Alps, according to Konrad Steffen, a climatologist at the University of Colorado, Boulder.
Mead Treadwell, the chairman of the U.S. Arctic Research Commission, predicted that there eventually will be "new shipping routes across the Arctic" because polar sea ice is melting.
That would halve shipping costs and save 40 percent of the time it now takes to travel from the Atlantic to the Pacific Ocean, he said—one way in which global warming might benefit, instead of harm, the Earth.
Antarctica, meanwhile, is gaining ice in the center of the continent but losing large chunks around its fringes, contributing to sea-level rise.
A prime concern during the IPY will be the fate of the world's glaciers, not only in polar regions but also in higher altitudes at lower latitudes near the equator.
Glaciers are "sentinels of climate change," said Mark Myers, the director of the U.S. Geological Survey.
"All the glaciers in the tropics are retreating," said Lonnie Thompson, a researcher at Ohio State University in Columbus who's spent 30 years studying glaciers in South America, Africa and the Asian Himalayas.
In the Himalayas, 22 percent of the ice disappeared in the last four years, Thompson said. One glacier in the Peruvian Andes is likely to be gone within the next five years, he said. Tanzania's famous Kilimanjaro peak will lose its remaining ice by 2015, if not before.
"This widespread retreat of mountain glaciers may be our clearest evidence of global warming," Thompson told the American Association for the Advancement of Science last month.
"It's too late for some of these glaciers," he said. "Millions of people are going to have to adapt to these changes, many of which will occur in some of the poorest regions of the globe."
Global warming's impact also is becoming clear in the mountain areas of the American West.
Henry Diaz, a NOAA climatologist in Boulder, Colo., said average temperatures in the West had risen by 2 degrees Fahrenheit since the mid-1970s, twice as fast as the global warming rate. That's because much of the West lies above 5,000 feet, and warming increases at higher elevations, he said.
"Our high mountains are like the third pole of the planet," Diaz said. "It's the world's coldest regions that are most susceptible to warming. Now our records are starting to show this acceleration."