We will not overcome world poverty unless we manage climate change successfully. I've spent my life as a development economist, and it's crystal clear that we succeed or fail on winning the battle against world poverty and managing climate change together. If we fail on one, we fail on the other.

Fortunately poorer countries, such as China, are showing leadership and beginning to demonstrate to the world how to invest in low-carbon growth.

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.

Meat is a wasteful use of water and creates a lot of greenhouse gases. It puts enormous pressure on the world's resources. A vegetarian diet is better.

Climate change is a result of the greatest market failure the world has seen...We risk damages on a scale larger than the two world wars of the last century.

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

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.