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Wednesday, October 29, 2003 - Page updated at 12:03 A.M.
Signs of radical change in Arctic ecosystem
By J. Patrick Coolican
Shrubs are appearing where before there were none; gray whales are venturing farther north; clams and their predators, diving sea ducks, are less plentiful. The ice is melting.
These disparate phenomena are signs of a radical change in the Arctic ecosystem. Moreover, changes in the Arctic mean changes everywhere else. That consensus is part of a broad discussion among 400 Arctic scientists meeting in Seattle this week as part of a new multimillion-dollar effort to study the far-reaching changes occurring in the far north.
The Study of Environmental Arctic Change (SEARCH), sponsored by the National Science Foundation and based at the University of Washington, has brought together climatologists, biologists, oceanographers and social anthropologists to examine how warmer temperatures are altering life on the tundra and how the changes may affect the rest of the Earth.
Their findings, presented at a symposium yesterday, continued to add to a growing, and somewhat ominous scientific consensus.
The Arctic, which has seen temperatures increase 3 to 4 degrees Fahrenheit over the past century, is on track to become as warm as it has been in 130,000 years, according to Jonathan Overpeck, a University of Arizona paleoclimatologist, who studies the history of climate change.
The conference and its research outgrowth will help establish a key unknown, Overpeck said: What is the point of no return? The point at which a reduction in greenhouse emissions will no longer matter? When will life be inexorably changed? (Overpeck said that although there's a broad scientific consensus that human beings are responsible for the recent warming, there are dissenting scientists, who say the change is not caused by human activity.)
In an interview after the symposium, Overpeck laid out potential consequences of the warming:
Warmer temperatures could lead to the melting of the vast field of ice that currently carpets about 80 percent of the island of Greenland. (Arctic sea-ice thickness reached its lowest recorded level in September 2002.)
That could lead to a 6-meter rise in sea levels, flooding coastal areas. Scientists are still trying to find out how long this process could take, Overpeck said.
The melting also could disrupt the conveyor of warm ocean currents that make places like England habitable as opposed to barren, icy outposts.
"The Arctic will change the globe," Sturm said.
Researchers also are examining how the climate changes will affect people living in the Arctic.
"Ice is a portal of life, an extension of the land" for indigenous communities, said Caleb Pungowiyi, a social anthropologist who lives in the Arctic region.
Although indigenous populations are wary of the effects of climate change, there could be good effects, like a larger caribou population and less populous insect swarms, Pungowiyi said.
The warmer Arctic is definitely changing life for plants and animals, according to Jacqueline Grebmeier, an oceanographer at the University of Tennessee. She noted plants growing on what was once a barren tundra, odd migratory patterns, disappearing species.
Studying changes in the Arctic will help scientists understand how future climate change will affect life in the more southern latitudes, said Mark Nuttall of the University of Alberta.
"The Arctic is the canary in the mine shaft. A barometer for the future," he said.
Implicit in a radical climate change, Overpeck asserted, is a mass species extinction.
There have been five known mass species extinctions meaning more than 50 percent of the Earth's species were wiped out and four were related to climate change, Overpeck said.
Unlike in the past, however, when plants and animals could freely adapt to climate change, Overpeck said, this time human development stands in the way big-box stores and factories and casinos and subdivisions that will prevent species from seeking new habitats.
"We're really playing with fire," he said.
J. Patrick Coolican: 206-464-3315 or email@example.com
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