Some people think the rhetoric of climate change is too emotive. But faced with a global catastrophe it would be unwise to tone down our language.

We are all familiar by now with the shrill voices of climate change deniers. But with every passing week they become more and more irrelevant, as their 'scepticism' about the reality of man-made climate change is exposed as risible. The issue now is not whether we are certain that dangerous climate change is real and is happening - the issue is only how we are going to tackle it. So how do we motivate people to act? How do we persuade them not to seek refuge in psychological defence mechanisms of the kind Leo Hickman chronicled in the Guardian last week?