U.N. Secretary-General Ban Ki-moon has urged the United States to take the lead in the search for a global response to climate change. VOA's correspondent at the United Nations, Peter Heinlein, reports the secretary-general described global warming as a threat at least as great as war.

Mr. Ban praised America's role in developing innovative technology to reducegreenhouse gas emissions.

Speaking to a group of students Thursday at U.N. headquarters, the secretary-general noted that, while Washington has not signed the Kyoto Protocol on climate change, discussions in the Bush administration and Congress have raised public awareness about global warming.

Answering a student's question, Mr. Ban expressed hope that the United States, the world's largest greenhouse gas emitter, would also take the political lead in searching for a successor to the Kyoto treaty, which expires in 2012.

He said, "I hope that the United States, while they have taken their role in innovative technologies, as well as promote cleaner energies, will also take lead in these very important and urgent issues which [the] international community must look for beyond Kyoto Protocol for the common prosperity of the human being in the future."

In his speech to the students, Mr. Ban described himself as a child of the Korean War, and recalled his youth in South Korea under the constant threat of a nuclear winter. But he said the environmental threat facing the globe today is just as serious.

"Today, war continues to threaten countless men, women and children across the globe," he said. "It is the source of untold suffering and loss. And the majority of the U.N.'s work still focuses on preventing and ending conflict. But the danger posed by war to all of humanity - and our planet - is at least matched by the climate crisis and global warming."

The U.N. chief said the world needs "a more coherent system of international environmental governance" to meet the challenge. He pointed to the world body as the natural choice for creating such a system.

"These issues transcend borders," he said. "That is why protecting the world's environment is largely beyond the capacity of individual countries."

"Only concerted and coordinated international action - supported and sustained by individual initiative - will be sufficient. The natural arena for such action is the United Nations," he continued.

The chief U.S. climate negotiator this week said the United States remains committed to the U.N. Framework Convention on Climate Change.

Negotiator Harlan Watson said even though the United States has not signed the Kyoto Protocol to the Framework agreement, and even though emerging economic giants such as India and China are exempt from its requirements, all three are working to cut harmful carbon emissions.

Watson defended the Bush administration's decision to stay out of the Kyoto regime, arguing that its requirements would cost an estimated $400 million a year and result in the loss of nearly five million U.S. jobs.