Secretary-General Ban Ki-moon expressed hope Thursday that the "active debate" in the U.S. administration and Congress on global warming will spur the United States to take a leadership role in combatting climate change.

The U.N. chief was addressing a student conference on global warming that brought hundreds of high-schoolers from around the world to the U.N. General Assembly hall.

One student asked what Ban thought about the rejection by President Bush's administration of the Kyoto protocol, a 1997 pact that requires 35 industrial nations to cut their global-warming gases by an average 5 percent below 1990 levels by 2012.

"I have a sense of active discussion within the U.S. government and Congress regarding the Kyoto protocol," Ban said. "And this kind of active debate has helped raise its profile and public interest in climate change."

Ban also said that climate change poses as great of a danger to the world as war.

"The majority of the U.N.'s work still focuses on preventing and ending conflict," Ban said. "But the danger posed by war to all of humanity _ and to our planet _ is at least matched by the climate crisis and global warming."

The Bush administration argues the Kyoto protocol would hurt the U.S. economy. Instead, the White House says it is spending almost $3 billion a year on energy-technology research and development combat climate change.

Ban, who took over as U.N. chief on Jan. 1, welcomed that effort, but said it's critical that the international community come up with a new strategy to deal with global warming after Kyoto expires in 2012. He added that climate change will be a top priority during his five-year term.

"I hope that the United States _ while they have taken a role in innovative technologies as well as promoting cleaner energies _ will also take lead in this very important and urgent issue," he said.

After years of arguing that not enough was known about the problem, Bush referred to global warming as an established fact in his State of the Union speech in January, and acknowledged that climate change needed to be addressed.

At a climate change forum in Washington last month, foreign lawmakers said that after hearing from U.S. lawmakers, they sensed a shift in Washington toward greater cooperation with other countries on global warming.

"I am encouraged to know that, in industrialized countries from which leadership is most needed, awareness is growing," Ban told the conference organized by the United Nations International School. "In coming decades, changes in our environment and the resulting upheavals _ from droughts to inundated coastal areas to loss of arable land _ are likely to become a major driver of war and conflict."

Bush's State of the Union address was the impetus, in part, for a proposal by the U.N. Environment Program to hold a summit on global warming later this year. Ban has not said if he will move forward with a summit.

But he said he would discuss how best to confront the problem with world leaders at a meeting of the Group of Eight industrialized countries in June.