The head of the United Nations Climate Change Conference is warning that a deadlock between the United States and the European Union over greenhouse gas emission targets may derail the conference. VOA's Nancy-Amelia Collins reports from the convention site in Bali.

From the start, officials here have emphasized that the aim of the Climate Change Conference is only to get negotiations started on a new global effort against climate change. These negotiations are to lead to a replacement for the Kyoto Protocol on climate change, which will expire in 2012.

However, a split has emerged at the conference here between the European Union and the United States, over whether or not to set firm targets for cuts in greenhouse emissions. Yvo de Boer, who is heading the U.N.-sponsored meeting, warned Thursday that the deadlock is threatening to derail the desired negotiations.

"I think what's at stake here for the United States, and in fact for everybody else that's here, is whether we can put in place in time a long-term climate policy that will kick in when the Kyoto Protocol's first commitment period expires in 2012," he said. "And I think everybody, including the United States, has come here with the stated desire to formally launch negotiations."

The dispute led European nations Thursday to threaten to boycott U.S.-sponsored climate talks next month unless Washington changes its mind.

The EU and the vast majority of the 190 nations participating in the conference want to set a target of a 25 percent to 40 percent cut in emissions. The U.S., along with Canada and Japan, are refusing to agree to any targets at this point.

The EU and others say it is important to set targets now, to get a head start in the fight against global warming. The U.S. says targets should come later, after negotiations begin.

The U.S., one of the world's two largest emitters of greenhouse gases, is the only major industrialized nation not to sign the Kyoto Protocol.

De Boer says scientific evidence of global warming should be sufficient to convince all nations of the need for urgent action.

"I think it will be incredibly difficult for any politician to leave here and go back home and explain that he or she has provided no political answer to what the scientific community has been saying," he said. "I think that that's what's at stake for everyone, including the United States."

The U.S. undersecretary of state for democracy and global affairs, Paula Dobriansky, is heading the U.S. delegation here. She says she hopes for a consensus before the conference ends Friday.

"We still have some work to do today and tomorrow," she said. "We are hopeful though that we can find a way to bridge remaining differences and reach consensus on a Bali road map."

Another point of contention here is a demand from developing nations that rich countries help poorer countries develop clean technology and clean sources of energy.