One of the major attractions of the treaty for Russia is a provision under which countries that have lowered their greenhouse gas emissions beyond the requirements can sell pollution credits to other nations that can't meet their treaty limits.
By some estimates, Russia -- where emissions have fallen by one-third since 1990 as production by heavy industries has slipped -- could gain more than $1 billion a year between 2008 and 2012 by selling credits.
Viktor Danilov-Danilyan, a former environment minister now at the Russian Academy of Sciences, said his nation could benefit from the pact in other ways. Russia has already used the treaty as a bargaining chip to win trade concessions from the European Union, and it could gain recognition for helping to slow global warming.
Despite Thursday's decision, Moscow has given mixed signals in the past over its willingness to back the treaty, prompting some observers to voice reservations about concluding that the issue is settled.
Boucher, the State Department spokesman, said it was not yet certain that the Russians would take all the steps needed for ratification. "The government has decided to submit it to the Duma, and it's not clear when the Duma would complete its role in the ratification process," he said.
Sergei Vasilyev, head of the National Carbon Union, a partnership of leading Russian businesses that advocates ratification, said "it does not seem possible that the government will backtrack on its words." But he added that parliament could drag its feet on ratification in order to extract concessions from treaty partners on details of implementation that still need to be worked out.
"It would mean that until the Europeans give valid and reliable guarantees to Russia, they will not have their Kyoto Protocol," he said.
Numerous Russian officials and academics continue to oppose the treaty, arguing that it will force costly upgrades in industry and that the science the pact is based on is unproven.
Russian Prime Minister Mikhail Y. Fradkov, speaking Thursday to reporters during a visit to the Netherlands, said he expected heated parliamentary discussion on the issue. "The debate is opened, and I think it will not be easy," he said.
Nonetheless, U.S. environmentalists praised Russia for acting on the accord -- and voiced scorn for the stance taken by their own government.
