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.

We can look back through ice-core data and see over 800,000 years, relationships between carbon dioxide and the temperature of the world. So those people who deny the importance of climate change are just wasting their time. They're also being diversionary because if we don't act the risks are enormous.

This [climate change] is potentially so dangerous that we have to act strongly. Do we want to play Russian roulette with two bullets or one?

There is still time to avoid the worst impacts of climate change, if we take strong action now.

To claim the World Bank is just an extension of US foreign policy is just wrong.

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.

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