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Arctic Warms Twice As
Fast As the Rest of the Planet
Climate
change has increased the melting of
ice and glaciers like Arctic sea ice, freshwater ice, ice shelves,
the Greenland ice sheet, Alpine and Antarctic Peninsula glaciers and
ice caps, snow cover and permafrost at an
incredibly rapid rate.
Global warming is warming the Arctic almost twice as fast as the rest of the planet, as the ice caps melt and expose the darker land surfaces. The exposed darker ground has a higher heat absorption power as compared to the less absorbing or more reflective nature of snow and ice. In addition, the smaller the area of sea ice, the less the incoming radiation will be reflected and thus more heat is absorbed. If sea ice continues to contract rapidly over the next several years, scientists would expect an Arctic amplification effect, with the rate of warming of the Arctic land mass to triple, and permafrost thaw to accelerate faster than predicted.
On land, the majority of Arctic ice is frozen in the Greenland ice sheet. Between 1979 and 2002, the extent of melting in Greenland has increased by an average of 16% – an area roughly the size of Sweden. More than 2 trillion tons of land ice in Greenland, Antarctica and Alaska have melted since 2003, according to new NASA satellite data. According to a report comprising the
research work of y more than 250
scientists, the Arctic Climate Impact Assessment (ACIA), (commissioned by the Arctic Council
and funded by the United States, Canada, Russia, Denmark, Iceland, Sweden,
Norway and Finland),
temperatures in the Arctic
will rise by 4oC - 8oC in the next 100 years.
The Greenland icecap would melt altogether in 1,000 years and
raise global sea levels by about 23
feet, presenting catastrophic
consequences to coastal regions around the world. The more immediate
impact is the sea level rise of about
4 inches by the end of the century with
total melting of the Arctic ice in
summers.
One of the remarkable features of the coastline of northern Ellesmere Island, Nunavut, is the presence of a series of ice shelves 4 500 years old, 10 - 50 m thick ice floating on the sea and attached to land. The Island, previously home to a single giant ice shelf, measuring about 10,000 square km has lost about 90% of its ice in the 20th century. By the year 2000 all that remained of this continuous icy fringe was a series of six ice shelves.
It is another dramatic sign yet of how rising temperatures and retreating sea ice are creating irreversible changes to the country's polar frontier. "Climate models indicate that the greatest changes, the most severe changes, will happen earliest in the highest northern latitudes..., this will be the starting point for more substantial changes throughout the rest of the planet.... Our indicators are showing us exactly what the climate models predict," said its director. Climate models forecast the occurrence of climate extremes such as hurricanes, cyclones and floods including Arctic thaw.
References and related news:
Two trillion tons of land ice lost
since 2003, rate of Greenland summer ice loss triples 2007
record
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