Carbon is the currency of how you measure climate change, but water will be the teeth.

Water and sanitation has not had the same kind of champion that global health, and even education, have had.

When you're working on development issues, optimism is not always based on rational analysis, often it is a moral choice.

We have to find climate-friendly ways of encouraging economic growth. The good news is we think they exist.

One of the most important things about leadership is that you have to have the kind of humility that will allow you to be coached.

No matter how good you think you are as a leader, my goodness, the people around you will have all kinds of ideas for how you can get better. So for me, the most fundamental thing about leadership is to have the humility to continue to get feedback and to try to get better - because your job is to try to help everybody else get better.

A lot of young people dont think they can make a difference. Thats really what I am at Dartmouth to do. Im there to tell the young people, Look, a few committed souls can change the world.