Unlike the big climate shifts of the geological past the one that is presently under way is a result of human activity. Despite a determined rearguard action by so-called sceptical environmentalists, there is no reasonable doubt that greenhouse gases released by industrialisation, together with the destruction of forest for farming and more recently bio-fuels, are at the back of global warming today. Possibly cosmic factors may also be at work – sunspot cycles, or whatever. But a mass of scientific evidence points to humanly produced carbon emissions over the past couple of hundred years as being the primary cause of the current process of global warming.

Humans started this process, and it is easy to conclude that humans can stop it. That has long been the Green refrain, now echoed by politicians in all parties. James Lovelock takes a different view: the planet is not a mechanism that humans can use as they please, winding it