An international team of scientists says the Arctic is warming much more rapidly than previously known because of the burning of fossil fuels around the world. Their four-year study says Arctic warming is occurring at nearly twice the rate of the rest of the world, with major impacts that are spreading far beyond the region, such as rising sea levels.
The 300 scientists who contributed to the report say concentrations of heat-trapping gases in the atmosphere, such as carbon dioxide, have caused a three to four degree Celsius rise in Arctic temperatures over the last 50 years. The report says the trend is expected to continue over the next century with an additional average temperature increase of three to five degrees over land and up to seven degrees over the Arctic Ocean.
The author, Susan Hassol, says the amount of Arctic Sea ice during the summer is expected to decline by at least half by the end of this century.
"Temperatures have gone up, the sea ice has retreated, the glacial mass is retreating, and the snow cover season is shortening," he said. "All of those are very strong evidence of warming from all around the Arctic. What you can see is even greater increases projected for the future than what we've seen in the past."
The scientific assessment was commissioned by the Arctic Council, a ministerial level organization composed of the United States and seven other nations with Arctic regions and six indigenous peoples' groups. The council will consider the findings at a meeting this week in Reykjavik, Iceland.
The report incorporates results from five major global climate models used by the United Nations Intergovernmental Panel on Climate Change.
The chairman of the panel who wrote the report, Robert Correll of the American Meteorological Society, says that if the Arctic ice cover declines as expected, polar bears and some seal species may become extinct and Arctic peoples will suffer severe economic consequences.
"Climate change is really happening in the Arctic and it is having deleterious effects on many systems," he said. "The preponderance of evidence is suggesting that it is creating some very difficult times for the people who live there, for the animals and plants that are residing there."
The impact will soon be felt beyond the Arctic, according to Michael McCracken of the U.S.-based non-profit organization the Climate Institute. He says the most pronounced global effect will be rising sea levels, which will inundate coastlines and other low areas.
"There's a lot of ice on Greenland. Once we start this melting going, it has the potential for raising sea level very significantly," he said. "We're not talking about sea level rise just in the Arctic. We're talking about sea level rise around the globe, so everybody is going to experience it, particularly regions that have low lying areas."
Two senators from the opposing U.S. political parties - Republican John McCain and Democrat Joseph Lieberman - say the report shows that global warming is making it more difficult for human society and wildlife to adapt. They again plan to propose a law requiring cuts in U.S. greenhouse gas emissions. Those are the gases that scientists say trap heat in the atmosphere and cause global warming. The senators' effort last year failed by seven votes in the 100 seat Senate.
President Bush rejects that approach and decided against allowing the United States to sign an international treaty that imposes such limits, the Kyoto Protocol. He argues that the accord would hurt American economic growth because he says it requires more of the United States than of other countries. Instead, he seeks voluntary cuts in greenhouse gas emissions and calls for an increase in government spending on climate change research.