I am President of the UN created University for Peace, which has a strong commitment to the relationship between peace, security and the environment. I meet with young people around the world and I always come away enthused and encouraged.

I am convinced the prophets of doom have to be taken seriously.

So, what we do as individuals matters. It adds up.

What pleases me most is that sustainable development is on almost everybody's agenda now.

If you want to maintain a sustainable supply of fish you have to farm the fish, rather than mine them. So putting your money into fishing fleets that are going to exacerbate the problem by over-fishing is not the way to preserve the underlying asset.

Don't accept that you can't make a difference. Because if you can't make a difference, you won't make a difference, and if you put a multiplier on that we will continue on an unsustainable pathway.

Strengthening the role the United Nations can play...will require serious examination of the need to extend into the international arena the rule of law and the principle of taxation to finance agreed actions which provide the basis for governance at the national level. But this will not come about easily. Resistance to such changes is deeply entrenched. They will come about not through the embrace of full blown world government, but as a careful and pragmatic response to compelling imperatives and the inadequacies of alternatives.