I had discovered long ago the first lesson of political courage: to think anew. I had then learned the second: to be prepared to lead and to decide. I was now studying the third: how to take the calculated risk. I was going to alienate some people, like it or not. The moment you decide, you divide.

And just as the terrorist seeks to divide humanity in hate, so we have to unify it around an idea. And that idea is liberty.

Today the impulse towards interdependence is immeasurably greater. We are witnessing the beginnings of a new doctrine of international community.

Politics may be the art of the possible; but, at least in life, give the impossible a go.

If we take all this actions and if it turns out not be true, we have reduced pollution and have better ways to live, the downside is very small. The other way around, and we don’t act, and it turns out to be true, then we have betrayed future generations and we don’t have the right to do that.

Real integrity means an answer. It doesn't just mean - it doesn't mean riding the anger. And this is very difficult to do.

Climate change is the world's greatest environmental challenge. It is now plain that the emission of greenhouse gases, associated with industrialization and economic growth...is causing global warming at a rate that is unsustainable.