The international equity question arises from the costs of climate change itself and mitigation varying greatly across countries. It is affected by the historical responsibility for current greenhouse gas emissions, which countries which were not responsible for what's in the atmosphere now think are very important. Currently rich countries don't think those issues are very important.

There is not going to be, we can be quite certain, there's not going to be any action on reducing greenhouse gas emissions by China or India or Indonesia or Brazil unless all developed countries are making a major effort. It will still be a big job to get them in, even if we are all making the effort. But our making the effort is a necessary condition.

It is a simple fact of life on earth that there is going to be no successful mitigation of the climate change problem without a truly global effort. All developing companies or all major developing countries have to be part of that and accept substantial constraints on greenhouse gas emissions.

Economic development over the past two centuries has taken most of humanity from lives that were brutal, ignorant and short, to personal health and security, material comfort and knowledge that were unknown to the elites of the wealthiest and most powerful societies in earlier times.

A revolution in humanity's use of fossil fuel-based energy would be necessary sooner or later to sustain and to extend modern standards of living. It will be required sooner if we are to hold the risks of climate change to acceptable levels. The costs that we bear in making an early adjustment will bring forward, and reduce for future times, the costs of the inevitable eventual adjustment away from fossil fuels.

A reduction in emissions matters more than what a country pays for it.

It crosses my mind that our generation may leave problems that are simply too hard for human society in the generations that follow. The structures that separate civilisation from disorder are thin and fragile. (But) I am not gloomy by nature so don't presume that the global community will fail the young people.