Green campaigners support Lovelock for sparking fresh debate on global warming

Leading British greens have taken a divided view of the prediction by the environmental scientist James Lovelock, featured inThe Independent yesterday, that the Earth has passed the point of no return for global warming.

Somefully shared his concern for the speed at which global warming appears to be proceeding, and gave credit to his scientific expertise, while finding themselves unable - or unwilling - to agree with the awesome proposition that it may already be too late to stop it.

"If any of us back up behind that idea we might just as well slit our wrists," said Aubrey Meyer, the director of the Global Commons Institute, which campaigns hard for an approach to limiting greenhouse gas emissions known as Contraction and Convergence, based on moving to equal emissions entitlements per person everywhere around the globe.

"But what [Professor] Lovelock is predicting will come true if we carry on as we are. To stabilise the rising concentrations, emissions must contract to nearly zero within ... 50 years."

Tony Juniper, the executive director of Friends of the Earth, said Professor Lovelock was right to sound the alarm. "But he's premature in writing humanity's obituary," he said. "There's still a narrow window of opportunity, and the priority must be to campaign for changes to make the most of that, not to assume that all is lost. "Assuming there's nothing to be gained means we're very likely to fail."

Professor Lovelock bases his predictions of disaster on the hypothesis that the Earth has for billions of years had a planetary-scale control system which keeps it fit for life - three decades ago he christened it Gaia.

The Gaia system, founded on the interaction of life-forms with their environment, is made up of feedback mechanisms that have previously acted in a benign way for humans. But because of the way the environment has been damaged by us, Professor Lovelock says, it may start to act in a way harmful to humanity and amplify global warming to such an extent that it is impossible to control.

Britain's most famous environmentalist last night declined to dismiss the too-late warning out of hand.

"If there was one scientist you would listen to on a proposition of that kind, it would be Jim Lovelock," said Jonathon Porritt, now head of the Government's Sustainable Development Commission. " Is he right? I simply don't know. I'm not enough of a scientist to make a judgement. With many people you would be tempted to dismiss the idea, but Jim is different."

Stephen Tindale, Greenpeace's executive director, also thought the man who conceived of Gaia might not be wrong. "The Earth may be doomed," he said. "Certainly the news from the natural world over the last year has been unremittingly bad: the oceans acidifying and less able to absorb carbon; the permafrost melting and giving up its methane ... All these things suggest that the positive feedbacks may have kicked in; we may have crossed the threshold. But we can't be certain, and so we can't give up the fight. While there is hope that catastrophe can be averted, we have a moral duty to keep trying.

"I believe that if governments take emergency action, climate change can still be controlled. So let's get on with it - and pray that we aren't too late."

Peter Melchett, the policy director of the Soil Association, shared a key concern of Professor Lovelock. "Right from the beginning there's a been a real worry that we would hit some point where the feedback mechanisms would all work against us," he said.

"But as to climate change being already unstoppable, I don't know, and I don't think Jim Lovelock knows either. There are still uncertainties about it all, and personally and instinctively I remain optimistic about the human race's ability to change direction ... It's our political and, shall we say, our psychological ability that's in doubt."

Mark Lynas, the author of High Tide - News from a Warming World, a travelogue showing places where global warming is already in evidence, said civilisational collapse was no longer just a scary possibility. "It's the most likely outcome if coal, oil and gas use continue to rise," he said. "Either we implement a radical programme to reduce our greenhouse gas emissions worldwide, or we need to start taking measures to prepare for post-collapse survival in the few areas which will remain habitable by the end of this century. The choice is ours.

"Lovelock telling us it's already too late should not be seen as an excuse for fatalism ... But his statements should be a reality check."