Alaska's not-so-permanent frost

Overlooking the snowcapped mountains and tidewater glaciers around Kachemak Bay, this hamlet of fishermen, artists, and tourists seems the picture of Alaskan charm.

But beneath the scene of plenty is a landscape parched: Three hot summers have dried local wells and forced the native village of Nanwalek to shuttle in bottled water and ration it. Swaths of spruce forest around Homer and the Kenai Peninsula are brown because of an unprecedented beetle infestation, linked to the warming climate. And snow levels have diminished steadily since 1938.

While much of the world knows global warming as a phrase, Alaska's warming climate is far more palpable. Summers here, as elsewhere, have been warmer and longer; winters are more temperate, with average temperatures climbing eight degrees Fahrenheit in three decades. Alaskans have mowed their lawns in November, golfed in February, and basked in record in record temperatures all summer.

"The most positive comments come from the more longtime Alaskans. They say, 'Heck, we've been through lots of tough winters. We deserve an easy one,'" says Jackie Purcell, meteorologist and weather anchor for Anchorage TV station KTUU.

Computer simulations of climate change have long suggested global warming's effects would be most pronounced at the poles. Researchers have tried to gauge the impact of the climate system's natural variations, and see if they can account for change over the last few decades.

However, most of the warming in Alaska is not due to these natural variations, says Michael Wallace, an atmospheric scientist at the University of Washington. Environmental changes in Alaska "suggest that global warming is playing a role."

The world should take note, adds Gunter Weller, executive director of the University of Alaska's Center for Global Change and Arctic System Research: "We are the canary in the mine shaft." Indeed, melting Alaskan glaciers are shedding twice as much ice as in previous decades. And the Arctic ice pack has thinned by 40 percent since the 1960s.

"There's no greater threat to Alaska's ecosystems and indigenous cultures than global warming. Period," says Deborah Williams, executive director of the Alaska Conservation Foundation. [Editor's note: The original version misstated the number of degrees rivers have warmed up in 20 years and slightly misstated a quote from Deborah Williams.]

Global warming is believed to be the result of rising amounts of carbon dioxide and other "greenhouse" gases in the atmosphere. These trap the earth's radiant heat, creating a greenhouse effect.

The effects are more dramatic here because of the temperature-sensitive overlay of permafrost and glaciers. Thawing permafrost plagues highway crews and operators of the Trans-Alaska Pipeline, which depends on supports to avoid sinking into the tundra. The oil industry has lost half its exploration season to the warmth, which keeps the tundra soft - and unable to support heavy vehicles or drilling equipment - for longer stretches of time.

Large sections of northern forests are collapsing into swamps of melting permafrost; sections of shoreline on the Arctic Coast have thawed, making them vulnerable to storms; and the Arctic's largest ice shelf, solid for 3,000 years, broke up last month due to warmer temperatures - though scientists were hesitant to blame global warming specifically.

"It's more than just mechanical erosion. It's melting of the soil. You can get big collapses of beach bluffs," says Craig George, a biologist with the North Slope Borough.

In rural villages, too, thawing permafrost wreaks havoc: Two Inupiat Eskimo villages on the northwestern coastline, Shishmaref and Kivalina, have lost so much ground they're in danger of washing into the sea. The villages are planning to relocate, at a cost of hundreds of millions.

Animals, meanwhile, are dealing with the retreating ice pack. With less time to escape from land in the spring, they sometimes wind up stranded on the outskirts of towns like Barrow. Polar bears have grown thinner in recent years, and some have to be killed as more migrate south. And the warming may have dire consequences for salmon in the Yukon River, the major food and income source for indigenous people along the 2,300-mile waterway.

Rivers have heated nine degrees Fahrenheit in 20 years, making mid-summer temperatures nearly lethal for salmon, says Richard Kocan of the University of Washington's School of Aquatic and Fisheries Science. With warmth comes increased infection by a parasite that seems to wipe out their reproductive abilities. And because the taste and texture of the meat has changed, fishermen harvest 150 salmon to get 100 usable fish, straining runs, Dr. Kocan says: "They don't feel right. They don't taste right. You can't sell them."

The economic toll alone, say some, should focus attention on Alaska. Disruptions to oil and fishing industries would damage the nation's economy, Dr. Weller points out, and the cost of rebuilding roads, airports and entire towns is staggering. Still, he says, "It hasn't been enough to convince the political system that something has to be done."

The state has launched a study to reevaluate regulations on tundra travel, which oil companies claim are too strict. And Gov. Frank Murkowski (R) is pushing for a permanent gravel highway on the western North Slope to take the place of the temporary ice roads that the oil industry has touted as environmentally friendly.

"You and I know that ice roads work, but it seems like winters are coming later and breaking earlier," the governor told a pro-development group earlier this year.

But a North Slope road is little consolation for regular motorists, who may soon face new woes: frequent floods on major highways over the next 10 to 15 years as newly thawed soil clogs bridges and culverts, scientists say. The problem is most pronounced in the interior, where highways run through discontinuous permafrost and along shrinking glaciers.

State officials have warned that warmer winters will increase freeze-thaw cycles for mountain snowpack. That means Alaskans should expect more frequent avalanches, like the deadly snow slide that rumbled into a neighborhood in the Prince William Sound town of Cordova in 2000.

For native people - 17 percent of Alaskans - who depend on berries and wild foods, global warming is a particular threat. The natural world "is our classroom," says Sterling Gologergen, an environmental specialist with the Nome-based Norton Sound Health Corp. But in her region of Alaska, traditional whaling schedules have been disrupted by an earlier bowhead migration. Walrus hunters must travel farther, at greater risk, to find animals at the ice edge. Beavers, previously unknown in the region, are showing up in local streams, and their dams could interfere with water quality and fish runs.

Drastic changes in vegetation mean her mother in Savoonga, on the Bering Sea island of Gambell, must walk farther to find the plants she gathers in summer. The result could be a shift in diet - and intangible losses. "I have a grandson and he's 4," says Ms. Gologergen. "What if I don't get to show or do things I did with my kids?"