PowerSwitch

After the scale of Copenhagen, Cancun will be a downbeat affair. Heads of state will be largely absent. Even optimists only hope Cancun might be a stepping stone to a deal at the end of 2011.

Three things have gone wrong. First, the global recession has given politicians other priorities. Second, in international diplomacy, failure breeds failure. Having not delivered last year, few leaders want to invest political capital in another try. And finally, there is the cataclysm that has overtaken climate science in the meantime. “Climategate”—the release of damaging emails from the University of East Anglia’s (UEA) Climatic Research Unit—raised questions about the way climate scientists work; as did revelations about flaws in the 2007 assessment of the UN’s Intergovernmental Panel on Climate Change (IPCC). The most notorious was “glaciergate”: a claim that the Himalayan glaciers would melt away by 2035 was probably wrong by about three centuries.

All this has badly drained public confidence in climate forecasts. It may never fully recover and it may not deserve to. Although the basic science behind the argument that we are warming the world is sound, scientists have sometimes skated over the uncertainties about how it will play out. And some have resorted to dubious tricks to simplify their message.

That's what Cancun should be about - surveying the startling scientific evidence, and developing an urgent plan to change course. The Antarctic - which locks of 90 percent of the world's ice - has now seen eight of its ice shelves fully or partially collapse. The world's most distinguished climate scientists, after recording like this, say we will face a three to six feet rise in sea level this century. That means the drowning of London, Bangkok, Venice, Cairo and Shanghai, and entire countries like Bangladesh and the Maldives.

And that's just one effect of the way we are altering the chemical composition of the atmosphere. Perhaps the most startling news story of the year passed almost unnoticed. Plant plankton are tiny creatures that live in the oceans and carry out a job you and I depend on to stay alive. They produce half the world's oxygen, and suck up planet-warming carbon dioxide. Yet this year, one of the world's most distinguished scientific journals, Nature, revealed that 40 per cent of them have been killed by the warming of the oceans since 1950. Professor Boris Worm, who co-authored the study, said in shock: "I've been trying to think of a biological change that's bigger than this and I can't think of one." That has been the result of less than one degree of warming. Now we are on course for at least three degrees this century. What will happen?

The scientific debate is not between deniers and those who can prove that releasing massive amounts of warming gases will make the world warmer. Every major scientific academy in the world, and all the peer-reviewed literature, says global warming denialism is a pseudo-science, on a par with Intelligent Design, homeopathy, or the claim that HIV doesn't cause AIDS. One email from one lousy scientist among tens of thousands doesn't dent that. No: the debate is between the scientists who say the damage we are doing is a disaster, and the scientists who say it is catastrophe.

Lord Beria3 wrote:Good article in the Prospect on the politics of climate change.