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.

Give up meat to save the planet.

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.

The scientific evidence is now overwhelming: climate change presents very serious global risks, and it demands an urgent global response.

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.

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.

Enlightened self-interest from those involved in hydrocarbons should lead to the support of technologies enabling the clean use of hydrocarbons, such as carbon capture and storage, and not to the defence of deniers and cranks.