I think all countries need to aim to cut the CO2 emissions per person, taking account of externalities like imports and exports.

I hope that by 2050 the entire solar system will have been explored and mapped by flotillas of tiny robotic craft.

The important point there is that when people talk about a mean temperature rise of say two, three or four degrees that's a sort of global average which really is a signature of large scale change in climatic patterns.

I'm not a specialist in the science but I have followed it fairly closely and it seems to me that there is among the experts a clear consensus that potential climate change is something to worry about.

One of the computer models for a four degree temperature rise would give rise to a 10 degree temperature rise in Africa. And bear in mind also that in the depth of an ice age the mean temperature drop compared to the present was five degrees.

Science isn't just for scientists - it's not just a training for careers.

It used to be controversial whether smoking caused lung cancer, it used to be controversial whether HIV caused AIDS. Now, there are a few mavericks who deny those things. In the case of climate change, I think the debate is going the same way in that there is a strong consensus that it is a serious matter.