Seattle Mayor Greg Nickels' stance on environmental protection is paying off big for him at the U.S. Conference of Mayors in Chicago.

Yesterday, Seattle was named the country's Most Livable City greater than 100,000 because of the mayor's promotion of his Climate Protection Initiative, a city program meant to reduce pollution and improve quality of life.

Nickels also got the nod from the conference environmental and energy committees for his proposal that cities represented at the gathering agree to meet goals of the Kyoto treaty for reducing greenhouse-gas emissions. Both panels adopted Nickels' resolution unanimously, and the full conference will vote on it tomorrow.

"Seattle is looked at by other cities as an innovator," Nickels said about the livability award. "So it isn't a surprise that we won, but it is an honor."

More than 150 other cities were considered for the award. Trenton, N.J., won the same award for cities with a population of fewer than 100,000.

A conference spokeswoman said Seattle was selected as the most livable because of policies such as Seattle City Light's commitment to curbing greenhouse-gas emissions, and the city's "smart growth" strategies.

"I think it says two things," said Steve Nicholas, the mayor's environmental adviser. "I think it's a recognition that global warming is a local issue. Second, I think it's a recognition that Seattle has a great program."

Nicholas also said he was surprised that the Kyoto proposal, formally called the U.S. Mayors' Climate Protection Agreement, was passed so handily by the committees.

Under the agreement, cities would voluntarily try to reduce greenhouse-gas emissions by 7 percent of 1990 levels by the year 2012, as called for under the Kyoto treaty.

Neither the Bush administration nor Congress has agreed to the international treaty, and Nickels had expected strong opposition to his proposal.

The mayor doesn't expect that the cities' voluntary efforts would have much effect on a federal acceptance of the treaty.

But, Nickels said, "This is a great step in terms of a grass-roots action."

The mayor said he would be lobby other mayors as the conference continues today.

Nick Martin: 206-464-3896 or nmartin@seattletimes.com