Any successful international negotiation for reducing emissions must be based on four principles: the precautionary principle, the principle of sustainable development, the polluter-pays principle and the principle of equity. The strength of 'contraction and convergence' is that it satisfies all these principles.

The world won't come to an end, but the incidence of disasters will have a very big impact, and in ways we can't predict.... Rises in seas levels will displace millions of people. It's estimated there will be 150 million refugees by 2050, homeless as a result of global warming. It's how we deal with these problems that is as much the challenge as tackling the causes of global warming.

[O]ur long-term security is threatened by a problem at least as dangerous as chemical, nuclear or biological weapons, or indeed international terrorism: human-induced climate change. ... The impacts of global warming are such that I have no hesitation in describing it as a 'weapon of mass destruction.' Like terrorism, this weapon knows no boundaries. It can strike anywhere, in any form...