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"You may be looking at the future, there," he said. "You're kind of getting an intimation of what the whole environment around here would be like if it all, generally, got hotter and drier."

Behind Juday, a professor of forest ecology at the University of Alaska Fairbanks, stood a small group of some of America's most distinguished scientific minds. They came to Alaska to see the effects of global warming.

In addition to Rosenfeld, some of the others along for the five-day trip last week were California-Berkeley physicist and astrophysicist Dr. Richard Muller; Dr. Rosine Bierbaum, dean of the University of Michigan School of Environmental Science and one of the U.S. negotiators of environmental accords in Kyoto, Japan; and Dr. Henry Kelly, the president of the American Federation of Scientists.

The group spent all day Tuesday in and around Fairbanks before moving down the Richardson Highway on Wednesday, with plans to visit retreating glaciers and other evidence of warming throughout the state.

The trip was put together by the nonprofit Alaska Conservation Foundation, which is working to disseminate information about climate change to the rest of the country.

"The ACF has now taken global warming as a topic we think is critical to the U.S. and the world," said Deborah Williams, executive director of the foundation. "Americans care about domestic impact and Americans care about Alaska, so it's important to get the story out."

The story, according to a Tuesday morning talk given by Dr. Gunter Weller, director of International Arctic Research Center's Global Change and Arctic Research division, is that numerous scientific studies conducted over the last few years have demonstrated rising temperatures worldwide, and the trend is expected to continue.

One prime reason for the trend is the increased buildup of greenhouse gases - primarily carbon dioxide, methane and nitrous oxide - created by human activity and industry.

Such gases serve to trap the sun's heat in the atmosphere, where it would normally be reflected back into space. In the Earth's Arctic regions, Weller explained, average temperatures have increased several degrees Fahrenheit in the last few decades, and various climate models suggest temperatures could rise another 7 to 8 degrees Fahrenheit in Alaska by 2070.

There are several reasons the effect is more acute in circumpolar climes, Weller said. The main one is that even slight rises in temperatures can cause more snowmelt, which leads to more capturing of solar heat because the ground is darker and more absorbent than the snowpack.

The results, he said, are multifold: thinner and less extensive sea ice; rising sea levels, melting permafrost that collapses buildings and even forests; and plants, animals and insects ranging ever farther north. Shorter winters already have reduced the amount of time oil companies can use to build ice roads and platforms on the North Slope.

In UAF's Bonanza Creek research station off the Parks Highway, Juday showed the scientists a stand of white spruce and described a forest with problems. The woods have been thinning out, he said, and the trees have been under stress because of rising temperatures. With more heat but the same amount of water available, he said, it's harder for trees to survive, and they become more susceptible to insects such as bark beetles.

The result of rising temperatures, he explained, is decreasing viability for Fairbanks' resident trees, such as aspen, birch and spruce. Forests would be more sparse and trees would be smaller, different vegetation would move in, and some upland forests may be reduced to woodland or grassland, he said.