Every climate scientist has his or her own views on some issues that differ from the mainstream in detail. But the broad findings of the IPCC (Intergovernmental Panel on Climate Change) have general support amongst scientists with relevant specialist expertise. The broad wisdom of the IPCC is strongly contested by a small number, and a small minority, of reputed climate scientists. It is not contested by the large majority of specialists, and by the leaders of the relevant learned academies in the countries of great scientific accomplishment.

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.

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.

The climate change problem is at its heart an ethical problem. It's a problem of income distribution and it's a problem of income distribution with dimensions that we don't usually think about very much.

Every climate scientist has his or her own views on some issues that differ from the mainstream in detail. But the broad findings of the IPCC (Intergovernmental Panel on Climate Change) have general support amongst scientists with relevant specialist expertise. The broad wisdom of the IPCC is strongly contested by a small number, and a small minority, of reputed climate scientists. It is not contested by the large majority of specialists, and by the leaders of the relevant learned academies in the countries of great scientific accomplishment.

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 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.