BALI, Indonesia — European nations threatened today to boycott American-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 America 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 tomorrow, even if it meant putting aside goals for emissions cuts.

“You can do one of two things here,” Mr. 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.”

America, Japan, Russia, and several other governments refused to accept language in a draft document suggesting rich nations consider cutting emissions 25% to 40% 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 America — and, he hopes, by others. The January 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.

America has invited 16 major economies, including European countries, Japan, China, and India, to discuss a program of what are expected to be nationally determined, 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,” the top EU environment official, Sigmar Gabriel, said. “This is the clear position of the EU. I do not know what we should talk about if there is no target.”

The main goal in Bali is to kick start two years of intense dialogue about how to slow global warming and head off scientific predictions of rising sea levels, worsening floods and droughts, and losing plant and animal species.

The U.N. climate chief, Yvo de Boer, said he worried the American-EU deadlock could derail any consensus in Bali on how to proceed.

“I’m very concerned about the pace of things,” he said. “If we don’t get wording on the future, then the whole house of cards falls to pieces.”

The American delegation said that while it continued to reject inclusion of specific emission cut targets, it hoped eventually to reach an agreement that would be “environmentally effective” and “economically sustainable.”

“We don’t have to resolve all these issues … here in Bali,” the head of the American delegation, Undersecretary of State Paula Dobriansky.

The Kyoto Protocol requires 37 industrial nations to reduce greenhouse gas emissions an average 5% below 1990 levels by the pact’s expiration in 2012. Australia was the latest industrial country to ratify the pact, soon after Prime Minister Rudd was elected.

Bush rejected the Kyoto pact on the grounds it would harm the American economy and its provisions didn’t apply to poorer but fast-developing nations such as China and India, whose emission levels are growing fast.