azcentral.com
Climate change accelerates in Arctic, makes Alaska a model
Rachel D'Oro
Associated Press
May. 6, 2004 02:15 PM
ANCHORAGE, Alaska - Yes, shore ice is thinner, winter arrives later and spring comes sooner along Alaska's Arctic coast. But that doesn't add up to evidence of a warmer world for Charles Hopson, an Inupiat Eskimo whaling captain from Barrow.
"Everybody's talking about global warming. Where the hell is it? It's cold up here," the 60-year-old subsistence hunter said on a late March day when frigid winds pushed temperatures in the nation's northernmost town to 50 degrees below zero.
Hopson, who has spent his life noting weather conditions, considers global warming an unproven theory, possibly linked to natural factors such as the El Nino pattern of shifts in tropical Pacific Ocean temperatures.
Others believe industrial fallout is behind the accelerated pace of climate changes in the past four decades, including the shrinking of polar ice estimated as much as 40 percent.
But while debating the cause, no one disputes that climate change is occurring. And it is watched with special interest in the Arctic, where effects of warming appear first and with greatest intensity, in part because as snow and ice melt, the terrain quits reflecting sunshine and begins absorbing heat.
Some scientists believe changes happening in the Arctic now foreshadow changes to come in the Lower 48.
Here, temperature averages have inched up, buckling roads and shifting some supports on the 800-mile trans-Alaska oil pipeline. Alaska glaciers have drastically retreated, contributing 10 percent to 20 percent of the measurable rise in world sea levels. The year-around icepack is getting smaller, which could profoundly affect ocean circulation systems, plankton populations and other ecological conditions.
But are those deviations due to a modern cause or are they part of an ancient norm?
"We've seen a lot of change and we're trying to work through the chain of causality," said Richard Moritz, who heads the University of Washington's Polar Science Center in Seattle. "We have respected scientists who have no doubt it's man-caused. Others say the jury is still out on how much is man-caused and how much is natural variability."
A group of international researchers is exploring that issue in the Arctic.
The Western Arctic Shelf-Basin Interactions program is focusing on the Chukchi and Beaufort seas, an area surrounding Alaska that participants say is a bellwether of significant climate changes. The $25 million venture, funded in part by the National Science Foundation, is doing field research, including spring, summer and fall cruises aboard the U.S. Coast Guard Cutter Healy, a research vessel and icebreaker.
Scientists are studying marine carbon, temperatures, salinity, minerals, light transmission, plant and animal life, bacteria, currents, salinity and other conditions throughout the Arctic seas, hoping to assess climate change and its impacts.
"When the ice is pulled back, that changes the carbon cycle and brine formation, with an ultimate impact on the downstream ocean circulation," said chief researcher Jackie Grebmeier, a University of Tennessee biological oceanographer. "Another concern is the effects on local subsistence hunters. Plankton goes where the water goes and animals capable of moving follow them."
Eugene Brower, a 56-year-old Inupiat from Barrow, said animals that haul out on ice such as walrus and seals are drifting farther north as the polar icepack recedes. Brower says he must travel up to 25 miles from shore to find his prey these days - twice the distance of past years.
His observations are backed by NASA satellite surveys that show summer Arctic sea ice has shrunk about 10 percent per decade since 1980, and the winter icepack has also declined significantly. The NASA study found the permanent ice cover dropped to record lows in 2002 and 2003. Scientists say that without large ice masses, which reflect the sun's rays into the atmosphere, the earth absorbs more heat, contributing to further warming.
And with more open water, shorelines are increasingly vulnerable to powerful fall storms. Erosion is great in some northern coastal villages, including Shishmaref and Kivalina, threatening homes and turning sandy beaches into rocky fields.
"We've got some huge waves out there," Brower said. "Around here, some people are talking about moving buildings that are close to shore."
Changes vary from region to region, said scientist John Walsh of the International Arctic Research Center at the University of Alaska Fairbanks.
Overall, temperatures have increased by an average of 2 to 4 degrees over the last several decades. Studies show the North Slope and Alaska's Interior have warmed by as much as 7 degrees in spring, while the western coast in fall shows the least change. Spring arrives about a week earlier in the Interior, but the region has actually cooled by 1 or 2 degrees in the fall, an example of natural variability, Walsh said.
"I've a view that humans are contributing to the warming but that other factors are involved as well, such as shifts in wind and ocean currents," he said. "There seems to be a consensus emerging that warming is definitely there and humans definitely contribute to it, but that there are also contributing factors that are not human caused."
There was a similar warming trend in the 1920s and 1930s, with the most noticeable effect on the Arctic, which saw temperature averages rise between 2 and 4 degrees, Walsh said. The global average rise, however, was much smaller, only a few tenths of a degree. The latest warming followed after a cooling in the 1940s that lasted to the mid 1960s.
"In the last few decades there's been a global increase as high as a full degree," Walsh said. "That's what has people thinking there's more going on than just natural variability."
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