Obviously I don't want the planet destroyed, but that's too big a picture for me to cancel my holiday.Message board poster on BBC website "Would you reduce your flights?"
In my view, climate change is the most severe problem that we are facing today, more serious even than the threat of terrorism.
When we are dealing with human lives, the classical models of economics will not apply. We need to have some other basis by which we can value the kind of human dimensions that would be involved in assessing impacts.
There are many people who go from denial to despair without pausing on the intermediate step of actually solving the problem.
The danger is not that we will stop talking about climate change, or recognising that it presents an existential threat to humankind. The danger is that we will talk ourselves to Kingdom Come.
What people [must] do is to change their behaviour and their attitudes. If we do care about our grandchildren then we have to do something, and we have to demand that our governments do something.
The reason why I spend most of my time dealing with climate change is because I do believe that we can find an answer...the moment you cease to belief that, then it seems to me that you may as well give up and eat, drink and be merry...If you don't want to do that, then we have really got to give people hope.