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.

The greenhouse effect is something you can observe experimentally - and most people have observed the greenhouse effect themselves, in greenhouses. Yes?

I've never really had much of a career plan, and interesting opportunities kept cropping up.

If you look at all the serious scientists in the world, there is no big disagreement on the basics of this...it would be absolute lunacy to act as if climate change is not occurring.

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

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.

Those who say that climate change doesn't exist are being understood as the flat-earthers that they are, as the people who deny the link between smoking and cancer, as the people who denied the link between HIV and AIDS.