The polar bear, the ptarmigan and Inuit culture are probably already doomed by the amount of pollution in the atmosphere, a leading scientist said yesterday.

　　Prof Stephen Schneider, a climatologist from Stanford University, who first made his name in the 1970s by predicting a new ice age, was referring to the latest predictions by the Nasa space agency that the world faces an extra 0.6 degrees Celsius of warming as a result of fossil fuel emissions already in the atmosphere.

　　This is in addition to the 0.7C rise over the past century and the result of Earth's slow response to warming caused by greenhouse gases trapping heat that might otherwise radiate out into space.

　　Prof Schneider said that birds were migrating earlier and flowers blooming earlier. "This is not theoretical," he told the Exeter conference. "Nature is responding to a 0.7C warming. It seems completely obvious that there is a threat to the viability of many species on the Earth. They have to move, as they did before. But then they did not have factories, freeways and urban settlements to cross."

　　He said there was "danger in the pipeline", not all of which had yet been seen. That was because of the inertia in the Earth's climate, as we had to wait for the ocean temperature to catch up with the amount of heat already being trapped in the atmosphere by greenhouse gases.

　　Prof Schneider said the next stage of warming was likely to affect small islands, polar bears, mountain top ecosystems and unique and valuable cultures such as the Inuit.

　　Margaret Beckett, the Environment Secretary, agreed that most of the climate change expected over the next few decades was inevitable.

　　She told the conference: "We have to act now to limit the scale of the warming in the future and avoid even worse effects."

　　Dennis Tirpak, the conference chairman and a former member of the United States Environmental Protection Agency, said that rising demand for energy was driving global warming.