The US will increasingly see the risks of being left behind, and ten years from now they would have to start worrying about being shut out of markets because their production is dirty.

Looking back, I underestimated the risks. The planet and the atmosphere seem to be absorbing less carbon than we expected, and emissions are rising pretty strongly. Some of the effects are coming through more quickly than we thought then.

If coal is going to be used, the only response - because it is the dirtiest of all fuels - is that we have to learn how to do carbon capture and storage and we have to learn how to do it quickly on a commercial scale.

A rise of 5C would be a temperature the world has not seen for 30 to 50 million years. We've been around only 100,000 years as human beings. We don't know what that's like.

My father's generation's crisis was fighting fascism. Ours is fighting climate change. It is much harder because you can't see it, it is not an obvious threat. But the solution is in our hands.

Science and policy-making thrive on challenge and questioning; they are vital to the health of inquiry and democracy.

The US will increasingly see the risks of being left behind, and ten years from now they would have to start worrying about being shut out of markets because their production is dirty.