WASHINGTON - The polar ice cap is melting at an alarming rate due to global warming, according to NASA scientists, with satellite images showing the ice cap has been shrinking by 10 percent per decade over the past quarter century.
"It is happening now. We cannot afford to wait a long period of time for technological solutions," said David Rind of NASA's Goddard Institute for Space Studies in New York.
"Change is in the air -- literally," he told a press conference here Thursday.
By means of a special satellite launched last year to measure the thickness of the polar ice cap, NASA has confirmed that part of the Arctic Ocean that remains frozen all year round shrank at a rate of 10 percent per decade since 1980, NASA researcher Josefino Comiso said.
This undated NASA composite image shows a fully dark (city lights) full disk image centered on the North Pole. The image was made from a combination of AVHRR, NDVI, Seawifs, MODIS, NCEP, DMSP and Sky2000 catalog data. (AFP-NASA/File)
"The extent of Arctic sea ice that remains frozen all year reached record lows in 2002 and 2003," he added.
The polar ice cap expands in winter and contracts in spring and summer. The part of the ice cap that never melts, even in the warmest summers, is called the "perennial sea ice."
The oceans and land masses surrounding the Arctic Ocean have warmed one degree Celsius (two degrees Fahrenheit) during the past decade, scientists said.
Researchers at the National Aeronautics and Space Administration are worried because global warming speeds up as the ice cap melts, forming a vicious cycle.
"Snow and sea-ice are highly reflective because they are white," Comiso said.
"Most of the sun's energy is simply reflected back to space. With retraction of the ice cover, that means that less of surface is covered by this highly reflective snow and sea ice, and so more energy has been absorbed and the climate warms."
The warming trend has brought spectacular consequences. US and Canadian scientists reported in September that the largest ice shelf in the Arctic off Canada's coast has broken up due to climate change and could endanger shipping and drilling platforms in the Beaufort Sea.
The Ward Hunt Ice Shelf had been in place on the north coast of Ellesmere Island in Canada's Nunavut territory for at least 3,000 years.
"Small changes in ice could mean big impacts on the water cycle and ultimately the global climate," warned NASA.
The changes could alter ocean currents, the distribution of fish populations and precipitation averages over a wide area.
"One activity in the north is hunting of marine animals using sea-ice as a platform. When sea-ice retreats, it affects the communities up there," said University of Washington oceanographer Michael Seteele.
"The Arctic is changing rapidly. We should be concerned in the sense we need to simply recognize the change is here, is occurring and we may have to adapt to it," University of Colorado researcher Mark Serreze told reporters.
"Why the increase in global temperature?" he asked.
"Part of this is probably simply due to natural variability in the climate system," he added. "But the general consensus of the climate community is that part these changes are due to human impact."
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