Give up meat to save the planet.

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.

You'd see more floods like you've seen in Mozambique in 2000, you'd see more droughts like you saw in Kenya in the late 1990s, there would be a serious threat to the water flow down the Nile on which 10 countries depend.

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?

Do politicians understand just how difficult it could be, just how devastating rises of 4C, 5C or 6C could be? I think, not yet

It's very important that there should be cross-fertilisation between government and academia. Both parties can benefit from having a better understanding of how the other works.