The trillion pound bill: That's what this respected expert says the climate summit may cost the world each year. And yet, he argues, it will hardly change a thing

As you might expect, the UN Climate Change Conference in Paris, which reached an agreement yesterday to limit the rise in global temperature to less than 2C, has been an international festival of hot air.

The bland, suburban conference centre hosting the two weeks of talks is populated by oversized animal cut-outs – a blue giraffe, a red camel – that we attendees use as landmarks to find our way around.

You hear people shouting into their phone, ‘I’m waiting by the pink kangaroo!’ But the outwardly cheerful menagerie is actually a Noah’s Ark installation designed to remind delegates of the perils of inaction. Woe to the pink kangaroo if the delegates fail to halt global warming.