Wishful thinking is not sound public policy.

We need to invest dramatically in green energy, making solar panels so cheap that everybody wants them. Nobody wanted to buy a computer in 1950, but once they got cheap, everyone bought them.

I'm an old member of Greenpeace. I worried intensely, as I think most of my friends did, that the world was coming apart.

Obviously any group that has to have funding also needs to get attention to their issues.

Listen, global warming is a real problem, but it's not the end of the world. A 30-centimetre sea level rise is just not going to bring the world to a standstill, just like it didn't over the last 150 years.

Wishful thinking is not sound public policy.

I really try to say things as they basically are and it so happens that it is a good message that things are getting better, but there are still problems.