WASHINGTON -- A Montana professor testified Thursday that climate change will increase and intensify wildfires, while members of Congress and Forest Service officials grappled with how to pay for the increased costs of fire suppression.

Forest Service Chief Gail Kimball and several experts at a House hearing agreed that changes in temperature and precipitation patterns from climate change will cause longer and more severe fire seasons in the West. Kimball already has taken $300 million in the agency's 2009 budget away from other priorities to steer it toward firefighting, she said.

Steven Running, an ecology professor at the University of Montana who recently shared the Nobel Peace Prize, testified that the only way to deal with the problem in the long run is to reduce greenhouse gas emissions.

On the other side of the Capitol, a Senate subcommittee approved 4-3 a climate change bill that would reduce greenhouse gas emissions by establishing a pollution credit trading system. Sen. Max Baucus, D-Mont., voted for the bill and added a provision that would set aside $1.1 billion a year for fire suppression from the proceeds of auctioned carbon permits.

Sen. John Barrasso, R-Wyo., voted against the bill, but added amendments to give states money to ease any negative economic impacts and to allow Wyoming coal to qualify for capture and sequestration program incentives.

At a hearing of the House Select Committee on Energy Independence and Global Warming, several witnesses noted that since 1986, the fire season in the West has grown 78 days longer. That's a 20 to 30 percent increase, Running said, and roughly the same percentage increase can be expected over the next decades.

Projections show that in a century, two or three times as much land in the West will burn each year as does today, said Chairman Edward Markey, D-Mass.

Climate change influences wildfires through increased drought, earlier snowmelt, warmer temperatures and better breeding conditions for insects, witnesses said. The problem is complicated by the increasing number of homes being built on the edge of forests and parks.

Kimball agreed that climate change is a factor in increased wildfires, but said more information is needed before the agency can conclusively state the relationship between the two. She said forestry can make a very significant contribution to global mitigation of climate change.

Kimball said the number of fires that burned more than 100,000 acres has increased dramatically since 1990.

"I think we can demonstrate higher severity, larger fires and certainly over the last seven, eight years more frequent fires and a longer fire season," she said.

Kimball said the agency spent $1.34 billion on firefighting costs during the 2007 fiscal year and had to dip into other accounts for $100 million of that. She said she already had to find $300 million from other accounts, even including vegetation treatment, to find enough money for firefighting as she prepares the fiscal year 2009 budget.

"We've made some very difficult adjustments," she said.

She said federal agencies have treated 25 million acres of hazardous fuels out of an estimated 190 million acres with excessive fuels.

The agency will be publishing an "open space strategy" next month, looking at what's happening with forest land across the United States and making a number of suggestions on policy decisions for Congress to consider, she said.

Kimball said climate change in Montana has allowed insects that usually reproduce once a year to have multiple broods. The agency is working on the science to determine how birds, insects, plants and viruses will be affected.

She said a 2-degree rise in water temperature would mean that trout streams could no longer support trout. Grizzly bears in Yellowstone are being affected because they eat seeds from white bark pine, and those trees are moving to higher elevations, she said.

Running, who shared the Nobel as an author with the 2007 United Nations Intergovernmental Panel on Climate Change, said the increased wildfires are due in part to some natural recovery of forests over the last century, fire suppression policies taking away the natural equilibrium and earlier snow melt bringing northern forests into drought.

Summer temperatures in Western North America are predicted to rise 5 to 8 degrees Fahrenheit in the next 50 years, with no increase in precipitation.

"The western U.S. in particular is in for longer, hotter summers and I can conclude nothing else but that's going to increase wildfire dynamics," he said.

The IPCC authors want the public to know that the warming trend is human induced and that the early signs of a transition of our entire landscape already have begun, he said.

"In the long run, only reducing our fossil fuel emissions is going to get us ahead of this problem," Running said.

Rep. James Sensenbrenner, the top Republican on the panel, said "global warming alarmists" are using fear to push for regulations that will have little or no effect on the problem. He said "liberal environmentalists" have long fought to prevent the Forest Service from managing fires but that management techniques like forest thinning and fuel breaks must be used.

Michael Medler, president-elect of The Association for Fire Ecology and a professor at Western Washington University, cut his teeth as a firefighter at the 1988 Yellowstone fires. He said veteran firefighters told him then that he would never again see that kind of fire behavior, but that most summers now have record-breaking fires and more extreme fire behavior.

Firefighters have been forced to change tactics and strategies, he said, especially in the Northern Rockies. They have had to give up aggressively fighting fires in the forest and instead turned to large backfires and "point protection" of homes and communities. He argued for better zoning laws and increased use of proscribed fire and proactive fire management rather than reactive suppression.

Michael Francis of The Wilderness Society called for resources to be directed at local communities to help them be able to make local protection strategies.