But could it be that policy-makers and businesses are looking at this whole area of climate change from too fixed an angle? We have scientific studies — often contradictory — along with masses of data, but there is a grave danger that the general public is experiencing environmental fatigue, turning off from the subject rather than engaging with the issues raised.

One very rainy evening in December, in the run-up to Copenhagen, three "Green Gurus" came together to debate whether it was possible to live well with climate change. One of them, John Grant, is no stranger to the world of marketing. He was a co-founder of St Luke's, the innovative and socially aware London ad agency, and wrote the Green Marketing Manifesto.

His creative industry background has led to much of his working life focusing on behavioural change, trying to persuade people to live differently. In his view, the biggest problem with getting people to engage with issues like climate change is its "unimaginability".

At the debate he recalled a recent focus group in Newcastle. “One woman,” he said, “announced that if climate change was real there would be mass hysteria.” So, why isn't there? Partly because people can't get their heads round the scale of the problem. Yet while people won't change their habits for science, they just might for stories. Think back, says Grant, to the many ethical and environmental debates around genetically modified foods. “It was the story of Frankenstein foods, the repugnance of man tinkering with nature that was a key mobilising factor in deciding the British public and the tabloid media , and I don't think we have found those stories relating to climate change yet.”

Despite Barack Obama's appearance in Copenhagen, he still has to bring the voters with him — and in the US the public, according to a recent survey, now ranks climate change twentieth in a list of twenty, a 3% fall in just a year. “In our focus groups we are told that the topic doesn't keep people awake at night,” says Grant. “We hear stories about poor victims of polar bears wandering outside their normal territories, and farmers suffering hardship, but we don't have the feeling that it is an imminent threat, despite scientific data.”

His solution, in groups, is to open up a space where people can talk about it and share stories. He often refers to the Stern Review, The Economics of Climate. One way is to point out that the natural response to a small household leak, which would be annoying and expensive to fix, is to delay calling a plumber out. The Stern report, however, says that failure to take prompt action now is to risk the ceiling falling a couple of years in.

Likewise a spend of one or two percent of GDP now, a relatively moderate amount of money, could mitigate this problem. Yet if we don't we'll see a 20% drop in growth. It is an argument, he says, that makes people sit up in their seats. They want to offer their children a future. They want to fix the problem. They just need a good reason for doing so.