The New York Times, Andrew C. Revkin, Oct. 30, 2004
A comprehensive four-year study of warming in the Arctic shows that heat-trapping gases from tailpipes and smokestacks around the world are contributing to profound environmental changes, including sharp retreats of glaciers and sea ice, thawing of permafrost and shifts in the weather, the oceans and the atmosphere.
The study, commissioned by eight nations with Arctic territory, including the United States, says the changes are likely to harm native communities, wildlife and economic activity but also to offer some benefits, like longer growing seasons. The report is due to be released on Nov. 9, but portions were provided yesterday to The New York Times by European participants in the project.
While Arctic warming has been going on for decades and has been studied before, this is the first thorough assessment of the causes and consequences of the trend.
It was conducted by nearly 300 scientists, as well as elders from the native communities in the region, after representatives of the eight nations met in October 2000 in Barrow, Alaska, amid a growing sense of urgency about the effects of global warming on the Arctic.
The findings support the broad but politically controversial scientific consensus that global warming is caused mainly by rising atmospheric concentrations of heat-trapping greenhouse gases, and that the Arctic is the first region to feel its effects.
While the report is advisory and carries no legal weight, it is likely to increase pressure on the Bush administration, which has acknowledged a possible human role in global warming but says the science is still too murky to justify mandatory reductions in greenhouse-gas emissions.
The State Department, which has reviewed the report, declined to comment on it yesterday.
The report says that "while some historical changes in climate have resulted from natural causes and variations, the strength of the trends and the patterns of change that have emerged in recent decades indicate that human influences, resulting primarily from increased emissions of carbon dioxide and other greenhouse gases, have now become the dominant factor."
The Arctic "is now experiencing some of the most rapid and severe climate change on Earth," the report says, adding, "Over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social and economic changes, many of which have already begun."
Scientists have long expected the Arctic to warm more rapidly than other regions, partly because as snow and ice melt, the loss of bright reflective surfaces causes the exposed land and water to absorb more of the sun's energy. Also, warming tends to build more rapidly at the surface in the Arctic because colder air from the upper atmosphere does not mix with the surface air as readily as at lower latitudes, scientists say.
The report says the effects of warming may be heightened by other factors, including overfishing, rising populations, rising levels of ultraviolet radiation from the depleted ozone layer (a condition at both poles). "The sum of these factors threatens to overwhelm the adaptive capacity of some Arctic populations and ecosystems," it says.
Prompt efforts to curb greenhouse-gas emissions could slow the pace of change, allowing communities and wildlife to adapt, the report says. But it also stresses that further warming and melting are unavoidable, given the century-long buildup of the gases, mainly carbon dioxide.
Several of the Europeans who provided parts of the report said they had done so because the Bush administration had delayed publication until after the presidential election, partly because of the political contentiousness of global warming.
But Gunnar Palsson of Iceland, chairman of the Arctic Council, the international body that commissioned the study, said yesterday that there was "no truth to the contention that any of the member states of the Arctic Council pushed the release of the report back into November." Besides the United States, the members are Canada, Denmark, Finland, Iceland, Norway, Russia and Sweden.
Mr. Palsson said all the countries had agreed to delay the release, originally scheduled for September, because of conflicts with another international meeting in Iceland.
The American scientist directing the assessment, Dr. Robert W. Corell, an oceanographer and senior fellow of the American Meteorological Society, said the timing was set during diplomatic discussions that did not involve the scientists.
He said he could not yet comment on the specific findings, but noted that the signals from the Arctic have global significance.
"The major message is that climate change is here and now in the Arctic," he said.
The report is a profusely illustrated window on a region in remarkable flux, incorporating reams of scientific data as well as observations by elders from native communities around the Arctic Circle.
The potential benefits of the changes include projected growth in marine fish stocks and improved prospects for agriculture and timber harvests in some regions, as well as expanded access to Arctic waters.
But the list of potential harms is far longer.
The retreat of sea ice, the report says, "is very likely to have devastating consequences for polar bears, ice-living seals and local people for whom these animals are a primary food source."
Oil and gas deposits on land are likely to be harder to extract as tundra thaws, limiting the frozen season when drilling convoys can traverse the otherwise spongy ground, the report says. Alaska has already seen the "tundra travel" season on the North Slope shrink to 100 days from about 200 days a year in 1970.
The report concludes that the consequences of the fast-paced Arctic warming will be global. In particular, the accelerated melting of Greenland's two-mile-high sheets of ice will cause sea levels to rise around the world.