Remember the green old days? They seem like only last year. In fact they were only last year: according to one long-running opinion poll, concern for the environment among consumers reached a peak in January 2007. Since then it has all but disappeared.

It is not hard to see why. Those were the days when the formidably named duo of Gore and Stern were rewriting the politics of climate change. Sir Nicholas Stern (now Lord Stern) offered a heavyweight analysis of its economics. Former US vice-president Al Gore campaigned with his documentary, An Inconvenient Truth, earning both an Oscar and a Nobel Prize. Heady days indeed for environmentalism.