BALI, Indonesia — In a dramatic finish to a U.N. climate conference, world leaders adopted a plan yesterday for negotiating a new global warming pact by 2009, after America backed down in a battle over wording supported by developing nations and Europe.

The American stand had drawn loud boos and sharp rebukes — “Lead … or get out of the way!” one delegate demanded — before Undersecretary of State Paula Dobriansky reversed her position, clearing the way adoption of the so-called “Bali Roadmap.”

“The United States is very committed to this effort and just wants to really ensure we all act together. We will go forward and join consensus,” she said.

The sudden reversal was met with rousing applause.

The upcoming two years of talks, which will hammer out a successor to the 1997 Kyoto Protocol, could determine for years to come how well the world will cut emissions of greenhouse gases blamed for global warming. A year of scientific reports have warned that rising temperatures will cause widespread drought, floods, higher sea levels, and worsening storms.

“This is the beginning, not the end,” Secretary-General Ban. “We will have to engage in more complex, long and difficult negotiations.”

The document does not commit countries to specific actions against global warming. It was limited to setting an agenda and schedule for negotiators to find ways to reduce pollution and help poor countries adapt to environmental changes by speeding up the transfer of technology and financial assistance.

All-night negotiations had appeared on the brink of collapse several times. Mr. Ban made an urgent plea for progress in the final hours of talks, expressing frustration with last-minutes disputes. He later praised America for compromising in the end.

“I am encouraged by, and I appreciate the spirit of flexibility of the U.S. delegation and other key delegations,” he said.

European and American envoys dueled into the final hours of the two-week conference over an EU proposal to suggest an ambitious goal for cutting the emissions of industrial nations — by 25 to 40% below 1990 levels by 2020.

The guidelines were eliminated after America, joined by Japan and others, argued that targets should come at the end of the two-year negotiations, not the beginning. An indirect reference was inserted as a footnote instead.

Just when it appeared agreement was within reach this morning, developing nations argued that their need for technological help from rich nations and other issues needed greater recognition in the document.

China angrily accused the United Nations of pressuring nations to sign off on the text even as sideline negotiations continued. That prompted an emotional spat that ended when a tearful and exhausted U.N. climate chief, Yvo de Boer, was escorted out of the hall.

In an apparent resolution, India and others suggested minor adjustments in the text that encouraged monitoring of technological transfer to make sure rich countries were meeting that need.

The EU backed the changes, but America objected, calling for further talks. Delegates by turns criticized and pleaded with Ms. Dobriansky to reverse course.

“We would like to beg them,” the Ugandan environment minister, Jesca Eriyo.

The applause that followed the Ms. Dobriansky’s reversal was one of the few times America won public praise at a conference studded with accusations that Washington was blocking progress.

She told reporters later that other delegations had convinced America that developing nations did not intend to dilute their commitment to take steps to stop global warming.

“After hearing the comments … we were assured by their words to act,” she said. “So with that, we felt it was important that we go forward.”

Environmentalists and other critics of the American position cheered the reversal.

“We have learned a historical lesson: if you expose to the world the dealings of the United States, they will ultimately back down,” the director of WWF’s Global Climate Change Program, Hans Verolme, said.

Environmentalists praised the final agreement, though some critics complained it lacked specific greenhouse gas cuts for industrialized nations, and did not include strong commitments for rich countries to provide poorer ones with green technology.

For developing countries, the final document instructs negotiators to consider incentives and other means to encourage poorer nations to curb — voluntarily — growth in their emissions. The explosion of greenhouse emissions in China, India, and other developing countries potentially could negate cutbacks in the developed world.

The roadmap is intended to lead to a more inclusive, effective successor to the 1997 Kyoto Protocol, which commits 37 industrialized nations to cut greenhouse gases by an average of 5% between 2008 and 2012.