I've never really had much of a career plan, and interesting opportunities kept cropping up.

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

I think that once people understand the great risks that climate change poses, they will naturally want to choose products and services that cause little or no emissions of greenhouse gases, which means 'low-carbon consumption.' This will apply across the board, including electricity, heating, transport and food.

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

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?

Science and policy-making thrive on challenge and questioning; they are vital to the health of inquiry and democracy.

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.