The Arctic is warming much more rapidly than previously known, at nearly twice the rate as the rest of the globe, and increasing greenhouse gases from human activities are projected to make it warmer still, according to an unprecedented four-year scientific study of the region conducted by an international team of 300 scientists.
At least half the summer sea ice in the Arctic is projected to melt by the end of this century, along with a significant portion of the Greenland Ice Sheet, as the region is projected to warm an additional 4-7° C (7 to 13° F) by 2100. These changes will have major global impacts, such as contributing to global sea-level rise and intensifying global warming, according to the final report of the Arctic Climate Impact Assessment (ACIA).
The assessment was commissioned by the Arctic Council (a ministerial intergovernmental forum comprised of the eight Arctic countries and six Indigenous Peoples organisations) and the International Arctic Science Committee (an international scientific organisation appointed by 18 national academies of science).
The assessment's findings and projections are being released today and will be presented in detail at a scientific symposium in Reykjavik, Iceland, November 9-12, 2004.
The assessment's projections are based on a moderate estimate of future emissions of carbon dioxide and other greenhouse gases, and incorporate results from five major global climate models used by the Intergovernmental Panel on Climate Change (IPCC).
"The impacts of global warming are affecting people now in the Arctic,"says Robert Corell, chair of the ACIA. "The Arctic is experiencing some of the most rapid and severe climate change on earth. The impacts of climate change on the region and the globe are projected to increase substantially in the years to come."
A Few Selected Findings
In Alaska, Western Canada, and Eastern Russia average winter temperatures have increased as much as 3-4° C (4 to 7°F) in the past 50 years, and are projected to rise 4-7° C (7-13°F) over the next 100 years.
Arctic summer sea ice is projected to decline by at least 50 percent by the end of this century with some models showing near-complete disappearance of summer sea ice. This is very likely to have devastating consequences for some arctic animal species such as ice-living seals and for local people for whom these animals are a primary food source. At the same time, reduced sea ice extent is likely to increase marine access to some of the region's resources.
Warming over Greenland is projected to lead to substantial melting of the Greenland Ice Sheet, contributing to global sea-level rise at increasing rates. Over the long term, Greenland contains enough melt water to eventually raise sea level by about 7 meters (about 23 feet).
Should the Arctic Ocean become ice-free in summer, it is likely that polar bears and some seal species would be driven toward extinction.
Arctic climate change presents serious challenges to the health and food security of some Indigenous Peoples, challenging the survival of some cultures.
Many coastal towns and facilities around the Arctic face increasing risks from erosion and flooding due to rising sea levels, decreased sea ice, and thawing coastal permafrost.
Over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social, and economic changes, and the Assessment has documented that many of these changes have already begun.
Arctic Climate Impact Assessment was formally initiated in 2000 at the
Ministerial Meeting of the Arctic Council at Point Barrow, Alaska as a
joint project implemented by the Arctic Council's Arctic Monitoring and
Assessment Programme (AMAP) and Conservation of Arctic Flora and Fauna
(CAFF) Working Groups, and the International Arctic Science Committee.
As specified in the Barrow Declaration, the goal of the ACIA is to evaluate
and synthesize knowledge on climate variability and change and increased
ultraviolet radiation, and support policy-making processes and the work
of the Intergovernmental Panel on Climate Change (IPCC)."The Arctic Council
directed ACIA to address "environmental, human health, social, cultural,
and economic impacts and consequences, including policy recommendations."