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

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.

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

Failing to curb the impact of climate change could damage the global economy on the scale of the Great Depression or the world wars by spawning environmental devastation that could cost 5 to 20 percent of the world's annual gross domestic product.

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

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

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.