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.

The basic scientific conclusions on climate change are very robust and for good reason. The greenhouse effect is simple science: greenhouse gases trap heat, and humans are emitting ever more greenhouse gases.

Adaptation is a vital part of a response to the challenge of climate change

My father's generation's crisis was fighting fascism. Ours is fighting climate change. It is much harder because you can't see it, it is not an obvious threat. But the solution is in our hands.

Climate change and global poverty are two sides of the same coin. Both challenges must be addressed together. If we fail on one, we will also fail on the other.

Climate change will affect the basic elements of life for people around the world - access to water, food production, health, and the environment. Hundreds of millions of people could suffer hunger, water shortages and coastal flooding as the world warms.

Looking back, I underestimated the risks. The planet and the atmosphere seem to be absorbing less carbon than we expected, and emissions are rising pretty strongly. Some of the effects are coming through more quickly than we thought then.