BALI, Indonesia - European nations threatened yesterday to boycott U.S.-sponsored climate talks next month unless the Bush administration compromises and agrees to a "road map" for reducing greenhouse gases blamed for global warming.

With the U.N. climate conference in its final hours, Nobel laureate Al Gore said the United States was "principally responsible" for blocking progress here toward an agreement on launching negotiations to replace the Kyoto Protocol when it expires in 2012.

But the former vice president urged delegations to reach the required unanimous agreement before the conference's end today, even if it meant putting aside goals for emissions cuts.

"You can do one of two things here," Gore said. "You can feel anger and frustration and direct it at the United States of America, or you can make a second choice. You can decide to move forward and do all of the difficult work that needs to be done."

The United States, Japan, Russia and several other governments refused to accept language in a draft document suggesting rich nations consider cutting emissions 25 percent to 40 percent by 2020, saying specific targets would limit the scope of future talks.

European nations and others argued that numerical goals are essential reference points in efforts to curb global warming.

All sides agree it is impossible to deal with climate change unless the United States is involved. It is the world's leading emitter of carbon dioxide and other greenhouse gases and the only major industrial country that did not ratify the Kyoto Protocol.

President Bush views his own climate talks as the main vehicle for determining action by the United States - and, he hopes, by others.

The Jan. 30-31 session in Honolulu is a continuation of September talks at the White House called the Major Economies Meeting on Energy Security and Climate Change. The United States has invited 16 major economies, including European countries, Japan, China and India, to discuss a program of what are expected to be voluntary cutbacks in greenhouse gas emissions. But the EU warned it would stay away unless Washington drops its opposition to mandatory cuts.

"No result in Bali means no Major Economies Meeting," said Sigmar Gabriel, the top EU environment official. "This is the clear position of the EU. I do not know what we should talk about if there is no target." *