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

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.

A diet that relies heavily on meat production results in higher emissions than a typical vegetarian diet. Different individuals will make different choices. However, the debate about climate change should not be dumbed down to a single slogan, such as 'give up meat to save the planet.'

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.