U.N. says global warming is coming fast.

The Earth is hurtling toward a warmer climate at a quickening pace, a Nobel-winning U.N. scientific panel said in a landmark report released Saturday, warning of inevitable human suffering and the threat of extinction for some species.

The potential impact of global warming is "so severe and so sweeping that only urgent, global action will do. Unless action is taken, human activity could lead to abrupt and irreversible changes that would make the planet unrecognizable".


President Bush has said that planned action against global warmed is flawed because major developing countries such as India and China, which are large carbon emitters, were excluded from any obligations. He also favors a voluntary agreement.

Sharon Hays, a White House science official and head of the U.S. delegation, said the certainty of climate change was clearer now than when Bush rejected Kyoto.

"What's changed since 2001 is the scientific certainty that this is happening," she said in a conference call to reporters late Friday. "Back in 2001 the IPCC report said it is likely that humans were having an impact on the climate," but confidence in human responsibility had increased since then.

"What's new is the clarity of the signal, how clear the scientific message is," said Yvo de Boer, the U.N.'s top climate change official. "The politicians have no excuse not to act."