A funky hodgepodge of old military trailers, canvas tents and a helicopter (to transport scientists to remote lakes and streams), the Toolik Field Station looks like some sort of 21st century "MASH" set. Established by the National Science Foundation in 1975 as a long-term ecological research facility, the site, nestled on the edge of Toolik Lake, has since attracted an annual crew of up to 100 scientists, graduate students and technicians from universities and institutions throughout the country. Each year they spend weeks at a stretch analyzing the changing landscape, isolated by the empty terrain from what they fondly call "their real lives."

Because the Alaskan Arctic is warming faster than any other place in the world, it offers an ideal natural laboratory to study climate change. Unlike the rest of the world, which has warmed about 1 degree over the past century, the Arctic's unique landscape of mostly ice and snow magnifies temperature changes because as ice and snow melt, the terrain stops reflecting sunshine and starts absorbing heat. With this trend in a dizzying rate of motion, computer models predict that during the next century the Arctic will warm an additional 7 to 12 degrees Fahrenheit. Considering that the last ice age was spurred by a temperature difference of 13 degrees, such climate change means that the flowers aren't alone in their strange behavior.

The tundra that Bret-Harte and Ray study is a patchwork of ancient grasses, berries, moss and woody shrubs. Due to the intense cold and the limitations of a two-month-long growing season, the plants are miniature -- 400-year-old tussocks are no bigger than a pie tin. Yet as the climate has warmed, the woody species like birch, willow and alder shrubs are not quite so shrublike these days. Compared with aerial photographs taken on oil exploration missions in the mid-1950s, the woody plants have taken off like a case of bad acne. In each of the 200 comparison photos, not only did individual shrubs increase in size, but the patches of alder and birch have spread into areas that weren't shrubby before. This trend is likely to continue, says Bret-Harte.

To further predict the outcome of future warming, in 1988 Bret-Harte's former postdoctoral advisor, Gaius Shaver, perched greenhouses directly atop the tundra. Inside the enclosed plot, the plastic structure increased the temperature by 3.5 degrees Celsius, the predicted regional warming for the next century. In less than 20 years, the birch has squeezed out the mosses and berries, growing from an average height of 8 inches to almost 4 feet.

"They're trying to become trees," says Bret-Harte, balancing on a boardwalk beside the crowded plastic greenhouse. While currently the birch lie down beneath the snow's weight, if and when the shrubs stay standing throughout the winter, they will trap snow. While it's hard to think of snow as bikini weather, for the soil in the north, snow actually acts as a thick blanket, creating a layer of insulation from the frigid wind and air. With more snow, soils could warm, releasing more carbon and other nutrients into the atmosphere and, that's right, contribute to more global warming.

A shrubbier landscape devoid of moss and grass could spell hard times for wildlife such as caribou, which feast on ground willow and cotton grass. Already caribou are feeling the proverbial heat: With warmer springs, plants are blooming earlier and then drying up earlier -- by as much as 10 to 20 days. That means less food in the fall, the critical time when caribou fatten up for the winter.

"Without ample forage, caribou aren't as able to conceive offspring or survive the long, cold winter," says Brad Griffith, an associate professor of wildlife ecology at the University of Alaska Fairbanks. Griffith suspects this shift in seasons is why the Porcupine caribou herd, the wildlife poster child in the fight over the Arctic National Wildlife Refuge, has dropped from 178,000 to 123,000 in the past decade.

Across the dusty Dalton Highway, in another watershed near Toolik, the landscape offers one more sign that global warming may already be having an impact. A wide hole, large enough to consume a helicopter, gapes from the tundra. Climb down into the pit and an underground world is exposed. A dense layer of rich soil and roots rests atop a slab of what looks like brown concrete. Called permafrost, this soil layer froze thousands of years ago, but as temperatures have warmed, it's melting. As these ancient slabs of ice dissolve, the spongy tundra tears off in large chunks and sinks a good 10 feet into the crater left by former permafrost. At the hole's lip, a small stream forms a waterfall, carving a new path, dense with soil and sediment under the landscape above.

"We've been walking around out here for 20 years and have never seen one of these things, and all of a sudden we've got four in our backyard," says William "Breck" Bowden, a professor of watershed science and planning at the University of Vermont, who has logged countless hours slogging across the tundra to study Arctic streams. For Bowden, these new formations are the biggest news of the summer -- the influx of mud is enough to smother the moss, algae and insects for up to 60 miles of river. While scientists aren't exactly a rash group, he makes a prediction: "This may be a tangible indication of the warming of the Arctic environment."

Not all permafrost melting results in such mud pits but, says Jon Benstead, a postdoctoral scientist from the Marine Biological Lab, the thawed soil is dumping additional nutrients into lakes and streams throughout the region. Benstead stands by the Kuparuk River in boots held together with duct tape.

As a heavy rain falls, he explains that to measure the impact of permafrost thaw, Toolik scientists have, for 20 years, been adding phosphorus to this river to mimic the nutrients that melting soil releases into the ecosystem. So far, the results have shown that with additional phosphorus, the river's algae flourish like an athlete on steroids. More plants translate into insect habitat and more food for fish. In this case, the changes of climate warming are beneficial for the plants and animals in the ecosystem.

Still, there's not a lot to throw a party over. Benstead adds that they're also seeing a trend: The Arctic grayling, one of only a handful of fish species sturdy enough to withstand the frigid winters, don't do well in warmer summers. He and his colleagues predict that if and when streams heat up to a measurable amount, the Arctic grayling may become extinct.

"There is no doubt that climate change is rewriting the rules that have governed these ecosystems for millennia," says Stan Senner, executive director of Alaska Audubon.

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