I've always been more interested in organisms that can move on their own than in stationary plants. But when I canoe or hike along the edge of lakes or oceans and see trees that seem to be growing out of rock faces, I am blown away. How do they do it?

The failure of world leaders to act on the critical issue of global warming is often blamed on economic considerations.

The future doesn't exist. The only thing that exists is now and our memory of what happened in the past. But because we invented the idea of a future, we're the only animal that realized we can affect the future by what we do today.

If America wants to retain its position as a global power, its president must listen to the people and show strong leadership at this turning point in human history.

Believe it or not, very little research has ever been funded to search for natural mechanisms of warming... it has simply been assumed that global warming is manmade. Climate change - it happens, with or without our help.

The climate is changing, but the question is how much - and to what extent human factors are contributing to that.

Green growth is one vehicle through which technology, globalisation and environmental challenges can be turned from obstacles to solutions for problems related to growth, jobs and competitiveness.

Climate change is happening, and humans are significant contributors, and that raises some really important policy questions.