Adaptation is the only means to reduce the now-unavoidable costs of climate change over the next few decades

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.

What we are talking about is extended world war...People would move on a massive scale. Hundreds of millions, probably billions of people would have to move.

Greenhouse gas emissions: Ultimately, stabilisation - at whatever level - requires that annual emissions be brought down to more than 80% below current levels

We run enormous risks and we know what kind of reductions of greenhouse gases are necessary to drastically reduce risks. Reducing emissions by half by 2050 is roughly in the right ballpark. It would bring us below 550 ppm.

Climate change represents the greatest and widest-ranging market failure ever seen

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.