The concept of national sovereignty has been an immutable, indeed sacred, principle of international relations. It is a principle which will yield only slowly and reluctantly to the new imperatives of global environmental cooperation. It is simply not feasible for sovereignty to be exercised unilaterally by individual nation states, however powerful. The global community must be assured of environmental security.

Licences to have babies incidentally is something that I got in trouble for some years ago for suggesting even in Canada that this might be necessary at some point, at least some restriction on the right to have a child.

Occupy World Street is a masterpiece which deserves to get wide circulation and commitment by world leaders.

I've got used to criticisms and, naturally, I try to make sure I don't listen to the more extreme ones because most of the people who have taken their rightwing extremist view of my life are people that I've never met.

I believe we are going to move into a situation where the more effective conferences will be smaller, more specialized, more focused, with occasional large gatherings to get the attention of the larger world.

I learn something from criticism because when it comes from sources you respect you always examine it and learn.

Nevertheless, the concept of sustainable development is now known - even amongst those who haven't accepted it - and it's recognized, debated and followed by an increasing number of businesses.