After years of debate among political and economic leaders here, the Russian cabinet on Thursday endorsed the 1997 Kyoto accord on global climate change. The move opens the way for likely ratification by parliament and implementation of the U.N. pact in the more than 120 countries that have embraced it.

Environmentalists around the world praised the cabinet's decision, which put the pact on a course out of a long legal limbo worldwide. The pact can take effect only if ratified by countries that together emit 55 percent or more of the carbon dioxide and other greenhouse gases that many scientists say are driving up global temperatures; Russian participation would push the count over that mark.

The Bush administration announced three years ago that it would not join in the accord, arguing it would be costly, slow economic growth and do little to protect the environment. With Russian participation all but certain, the treaty now appears set to proceed, which could bring new political pressure on the United States to join.

Environmental groups were almost universally ebullient at the news from Moscow. Fred Krupp, president of Environmental Defense, said it should bring "a moment of celebration and another decade of hard work. . . . In virtually every industrialized country, there will be a carbon limit. It's a historic step in an effort to secure our future."

By 2012, industrial countries that sign on to the pact are supposed to reduce emissions of the six greenhouse gases by 5.2 percent compared to 1990 levels. Countries that emit less than their quotas are free to sell emission rights to other countries that exceed their quotas.

Russia is in a position to reap billions of dollars through such sales, because by shutting down gas-belching Soviet-era industries, it has already cut its emissions to about 25 percent below 1990 levels.

There is heated debate over how much European countries and Japan will have to cut their emissions, because they will be able to buy allowances from Russia. William O'Keefe, president of the George C. Marshall Institute and an opponent of the pact, said Russian ratification "enables the E.U. to engage in creative accounting so they can meet their targets." But Jos Cozijnsen, a Dutch energy and environmental consultant, said the Europeans and Japanese "need more reductions than the Russians can sell."

Some specialists say Americans will feel the pact's effects even if the United States stays out. "The U.S. is not an economic island," said Phil Clapp, president of the National Environmental Trust. "Any U.S. company with a manufacturing unit in Europe is going to start wrestling with how to reduce its carbon emissions."

Kevin Fay, executive director of the International Climate Change Partnership, which includes such multinationals as DuPont and BP, said now that Kyoto has "gone from life support back to a possibility," his members will have to intensify work they are already doing on reducing emissions of carbon dioxide and other targeted gases."

Some advisers to President Vladimir Putin have opposed the pact, citing concerns of cost and questionable impact. But Russia has come under strong pressure from the European Union, whose 25 members need Russian quotas. At a meeting with European leaders in May, Putin signaled that he would support the agreement.

In return, the E.U. is to endorse Russia's membership in the World Trade Organization, a key foreign policy goal of the Putin government. Ratification will also burnish the country's international standing at a time when Putin has been under criticism for centralizing power.

"I think the image of the country will become much better," said Victor Danilov-Danilyan, a member of the Russian Academy of Sciences and a former minister of ecology and natural resources. "Russia had the key to the Kyoto Protocol, and when you have the key and you don't let anyone in, it is very impolite."

The Russian cabinet's endorsement "is a very welcome event," said Reijo Kemppinen, a spokesman for the European Commission, the E.U.'s executive arm, at a news conference in Brussels. "This will increase awareness of the fact that the Kyoto Protocol is extremely useful, and the more countries that join, the more influence it will have. We hope the U.S. will reconsider."

Russian ministries are to prepare legislation for the accord's ratification over the next three months. Prime Minister Mikhail Fradkov, who is in the Netherlands, was quoted by the Russian news agency Interfax as saying ratification was not certain. "The discussion on the subject is open and debate is likely to be difficult," he said.

But the State Duma, the lower house of parliament, is dominated by pro-Kremlin parties. Political analysts said that if Putin is committed to the treaty's passage, it will sail through. "The Duma does not say no," said Danilov-Danilyan.

Dirk Forrister, who chaired the White House climate change task force under President Bill Clinton in 1997-99 and now is managing director of Natsource, an environmental market broker, predicted that implementation is "going to increase the pressure on the U.S. to come up with a serious and sensible program."

Harlan Watson, the State Department's senior climate negotiator, said in an interview that administration officials are "going to continue to carry out the president's policy. We really don't believe there's bigger implications for us" from the Russian decision.

Watson said the administration was focused on investment in climate change research and new technology, such as sequestering carbon underground before plants can emit it and promoting hydrogen and nuclear power.

Democratic presidential nominee John F. Kerry has argued that too much time has passed to meet the specific goals set in 1997. He supports restarting international talks. Sens. John McCain (R-Ariz.) and Joseph I. Lieberman (D-Conn.), meanwhile, have drafted legislation that would establish a cap-and-trade program to bring carbon emissions back to 2000 levels by 2010.

Proponents of the protocol contend it is crucial to stopping what they call potential environmental catastrophe, the melting of ice that would raise sea levels and flood low-lying coastal areas, many of them densely populated. Critics contend that scientists have not definitively shown that greenhouse gases are causing global warming. They also cite the financial and social costs of shutting down polluting industries and installing new technology.

To date, 125 nations, accounting for 44 percent of emissions, have ratified the pact. Russia's share is about 17 percent. Russia and the United States, with a 35 percent share, were the last uncommitted industrial countries with high enough emission numbers to push the total past the 55 percent threshold.

Pact members that are classified as developing countries, including China and India, are meant to work toward reductions but are not legally bound to match the cuts of the industrial countries. Negotiations among members are scheduled to begin next year to set targets for after 2012. Analysts say that developing countries could come under pressure to make commitments for cuts.

Ratification could remain contentious in Russia, where officials continued to snipe at one another about the merits of the cabinet action.

"It's a political decision, it's a forced decision," said Andrei Illarionov, a presidential economic adviser and opponent of the pact. He compared it to fascism and said it would end Russia's ambition of doubling its gross domestic product in the next 10 years. "It's not a decision we are making with pleasure," he said.

But Alexander Bedritsky, head of federal meteorology service, said Russia "will not lose out." Speaking before the cabinet meeting, he said Russia could accrue billions of dollars by selling emission quotas.

Eilperin reported from Washington.

President Vladimir Putin had signaled to European leaders that Russia would support the Kyoto accord, but there is still disagreement among his advisers.