PORTLAND – Fresh from her trip to Alaska, Sen. Susan Collins said the environmental damage she witnessed has increased her determination to limit greenhouse gases.

Collins said Friday that she witnessed coastal erosion that threatens Eskimo villages in Alaska, devastation in forests in Alaska and the Yukon, and evidence of melting permafrost that caused utility poles to topple over.

“It strengthens my resolve to pass legislation that would establish declining limits for the aggregate amount of greenhouse gases that can be released,” she said.

Collins was joined on the trip by Sens. John McCain, R-Ariz., Lindsey Graham, R-S.C., and Hillary Clinton, D-N.Y. During the trip, they heard and saw evidence that the climate has been warming up and causing environmental problems.

They saw evidence that the permafrost had begun to thaw, weakening pilings on which homes were built and causing utility poles to topple, Collins said. Coastal villages are being hurt by coastal erosion as water levels rise.

They also saw the devastation wrought by the bark beetle on forests in both Alaska and Yukon Territory, she said. Scientists say bark beetles normally die during cold weather but they have been surviving warmer winters.

“I pressed the scientists hard on the issue of whether this is a natural cycle or whether it was caused by human activity. What they said was that the evidence was very strong that human activity has greatly exacerbated a natural cycle,” Collins said Friday.

McCain and Sen. Joe Lieberman, D-Conn., are sponsoring legislation that would limit greenhouse gas emissions from utilities and industry.

The Climate Stewardship and Innovation Act would cap U.S. emission levels at levels recorded in 2000. Opponents of the legislation include Sen. Ted Stevens, R-Alaska, chairman of the Senate Commerce, Science and Transportation Committee.

During the trip to Alaska, Graham said he was still undecided on the legislation, but Clinton said Friday she thought key lawmakers were beginning to come around.

“I don’t know exactly what the timing would be or what the vehicle would be, but I think finally we’ve reached a critical mass in the Senate,” said Clinton.

Collins favors a “cap and trade” program on greenhouse emissions that sets limits while letting the industry work together to achieve them.