MOSCOW — The long-delayed Kyoto Protocol on global warming overcame its last critical hurdle to taking effect around the world Thursday when Russia's Cabinet endorsed the treaty and sent it to parliament. The treaty, the first to require cuts in emissions linked to global warming, would take effect 90 days after parliament's approval, a formality that was widely expected.
The United States has rejected the treaty and will not be bound by its restrictions. But the treaty, which has already been ratified by 120 countries, will take effect if supporters include nations accounting for at least 55 percent of all industrialized countries' 1990-level emissions. The only way for it to cross that threshold was with ratification by Russia. In 1990, the United States accounted for 36.1 percent of emissions from industrialized countries, and Russia 17.4 percent.
The protocol was dormant over the past two years as Russia considered its merits and sought concessions from the European Union, the treaty's main proponent.
The treaty is widely considered a milestone of international environmental diplomacy. It is the first agreement that sets binding restrictions on emissions of heat-trapping gases that, for now, remain an unavoidable result of almost any facet of modern life, including driving a car and running a power plant. The main source of the dominant gas, carbon dioxide, is burning coal and oil.
But many specialists say that, at the same time, the protocol is just the tiniest initial step toward limiting the human influence on the climate, given that its targets are small and that major polluters, including the United States will not be bound by its terms. China, a major polluter that did sign the treaty, is not bound by its restrictions because it is considered a developing country.
The treaty would require 36 industrialized countries to reduce their collective emissions of six greenhouse gases by 2012 to more than 5 percent below 1990 levels, with different targets negotiated for individual countries.
By one calculation, it would take more than 40 times the emissions reductions required under the treaty to prevent a doubling of the pre-industrial concentration of carbon dioxide in the atmosphere in this century.
Still, the decision by the government of President Vladimir V. Putin to endorse the treaty was "cause for celebration," said Klaus Toepfer, the executive director of the U.N. Environment Program.
He acknowledged that the Kyoto accord was "only the first step in a long journey towards stabilizing greenhouse gas emissions."