By Eric Pianin, Washington Post Staff Writer

With the United States on the sidelines, negotiators for more than 160 countries, including Great Britain, Japan and Russia, reached agreement late last night on a groundbreaking climate control treaty setting mandatory targets for reducing greenhouse gas emissions.

European environmental leaders, who were outraged when President Bush disavowed the Kyoto global warming treaty in March, vowed to forge ahead without the United States and work out final details in Morocco this week. But the talks nearly collapsed and negotiators had to satisfy the last-minute demands of the Japanese, Russians and Australians for more flexibility in the rules and other economic advantages in order to close the deal.

"The global package is adopted," European Union spokesman Vincent Georis told reporters after 18 hours of talks that stretched into this morning, Morocco time. Officials said they expected the remaining countries to approve the details of the treaty.

The treaty would require about 40 industrialized countries to reduce worldwide emissions of carbon dioxide and other heat-trapping greenhouse gases by an average of 5.2 percent below 1990 levels by 2012. The governing bodies of at least 55 countries responsible for 55 percent of the world's greenhouse gas emissions must formally ratify the pact before it takes effect.

"This is the only international global warming treaty that begins the world on a downward trend of carbon dioxide emissions," said Jennifer L. Morgan of the World Wildlife Fund climate change campaign, who was in Morocco for the talks. "It sends a strong signal to the shrinking ranks of doubters in politics and business to tackle global warming."

The United States, the world's biggest emitter of greenhouse gases, would be exempt from the treaty. Yesterday, the Department of Energy reported that heat-trapping carbon dioxide emissions increased by 3.1 percent in the United States last year -- the biggest increase since the mid-1990s.

Carbon dioxide emissions, the chief cause of global warming, were nearly 14 percent higher than in 1990, according to the department's Energy Information Administration.

The Bush administration opposes the treaty, saying it would harm the U.S. economy while exempting developing countries, including India and China, from mandatory emissions targets. Instead, the White House has advocated spending more for scientific research, incentives for developing new technology to reduce emissions and other voluntary or market-based incentives.

White House Chief of Staff Andrew H. Card Jr. and other officials said last summer that the administration would likely present fresh proposals for revising the global warming treaty during the meeting in Morocco. But the administration has set aside its Cabinet-level review of alternatives to the Kyoto protocol in the wake of the Sept. 11 terrorist attacks. Undersecretary of State Paula Dobriansky, the head of the U.S. delegation, arrived at the conference with no new offers and largely stayed in the background while the talks proceeded haltingly.

Global warming remains a potent political issue in Europe and Japan. Many scientists who have taken part in U.N.-sanctioned climate change research have concluded that the buildup of heat-trapping chemicals in the atmosphere may cause temperatures to rise by 6 degrees to 12 degrees Fahrenheit this century. That increase is likely to provoke more violent storms, the melting of the polar ice caps and rising sea levels that could inundate small islands and many coastal areas.

While the Senate went on record in 1997 opposing the essential features of the Kyoto protocol, some prominent Republicans and Democrats have urged Bush to find a way to make the pact acceptable.

"How long can the administration turn its back on issues the rest of the world cares about -- from global warming to trade in small arms -- and expect broad support on issues like the war on terrorism?" said Philip Clapp, president of the National Environmental Trust.

However, Glenn F. Kelly, executive director of the Global Climate Coalition, an industry-backed group that opposes the treaty, said, "From what we see so far, once again the parties have done nothing to address fundamental concerns expressed by the United States for years."

The final agreement came after government environmental ministers -- eager to complete negotiations -- hurried in and out of small conference rooms in Marrakesh, arguing over what they called about a half-dozen "crunch" issues.

According to environmental groups and others monitoring the talks, the final disputes centered on how a set of proposed market-based mechanisms would function to mitigate the treaty's impact on the economies of the countries taking part.

The treaty's mandatory emissions cuts would most heavily penalize highly industrialized countries that use large quantities of coal and other fossil fuels to operate industrial sites and power plants.

The mechanisms were designed to help those countries meet their targets by allowing them to purchase carbon credits on an international financial market from countries with relatively small greenhouse gas emissions, or by reducing their quota by expanding forests and farmlands that absorb carbon dioxide from the atmosphere.

Some members of the European Union have long been skeptical of these mechanisms, arguing that they make it too easy for some major polluters to meet their goals.

The negotiators appeared to have made significant headway on Wednesday when all sides agreed on an enforcement mechanism that would penalize countries that failed to meet their goals by raising their emission reduction targets by 1.3 percent.

However, there was a major dispute over eligibility requirements for countries participating in credit trading. Officials last night did not immediately explain how they had resolved these differences.

The treaty framework was first negotiated in Kyoto, Japan, in 1997 but was subject to further detailed negotiations on how it would be enforced before it could be formally submitted to the legislatures of the participating countries for formal ratification.

During a session last summer in Bonn, the European Union, Japan, Russia and other principal participants agreed on almost every element of the accord but left some issues unresolved until the Marrakesh talks.