BONN, Germany -- Once booed at international climate talks, the United States won sustained applause Sunday when President Obama's envoy pledged to "make up for lost time" in reaching a global agreement on climate change.
Todd Stern also praised efforts by countries like China to reign in their carbon emissions, but said global warming "requires a global response" and that rapidly developing economies like China "must join together" with the industrial world to solve the problem.
The debut of Obama's climate change team was widely anticipated after eight years of obdurate participation in U.N. climate talks by the previous Bush administration.
"We are very glad to be back. We want to make up for lost time, and we are seized with the urgency of the task before us," Stern said to loud applause from the 2,600 delegates to the U.N. negotiations.
They clapped again when Stern said the U.S. recognized "our unique responsibility ... as the largest historic emitter of greenhouse gases," which has created a problem threatening the entire world.
The two-week meeting by 175 countries that began Sunday was the latest stage of talks aimed at forging a climate change agreement to replace the 1997 Kyoto Protocol on emissions targets for rich countries, which expires in 2012.
The United States was instrumental in negotiating Kyoto, but failed to win support at home. When George W. Bush took office, he renounced it, calling Kyoto a flawed agreement that would harm the U.S. economy and unfair because it demanded nothing from countries like China or India.
Stern said his team did not want a repeat of the Kyoto debacle. The latest agreement is due to be finalized in December in Copenhagen, Denmark.
"Ultimately, this is a political process," he said. "The way forward is steered by science and pragmatism."
Stern said no one on his team doubted that climate change is real.
"The science is clear, the threat is real, the facts on the ground are outstripping the worst-case scenarios. The cost of inaction or inadequate action are unacceptable," he said.