Depending on how quickly you get ocean rise, you have people who live in river deltas [at risk]. Bangladesh is largely a river delta, and the rising sea level means that when storms come in, the human sanitation is backing up, the ability to farm, it's destructive-type situations like you saw in New Orleans with Katrina. You're increasing the frequency of that stuff in low-lying areas fairly dramatically.

You can be a business thinker.

The key thing you can do to reduce population growth is actually improve health.

Going out in the field, it's always enlightening to see what's working and what's not and to sit down and talk - I was with young girls in south Africa - understanding why our tools for prevention aren't being adopted, and what way may need to invent to help protect them.

The nuclear approach I'm involved in is called a traveling-wave reactor, which uses waste uranium for fuel. There's a lot of things that have to go right for that dream to come true - many decades of building demo plants, proving the economics are right. But if it does, you could have cheaper energy with no CO2 emissions.

Helping convene global stakeholders to establish a set of measurable, actionable and consensus-built goals focused on extreme poverty is invaluable.

So not only are we saving lives now, we're creating the incentive for the breakthroughs that over the next generation will mean we can take AIDS, malaria and TB and bring those numbers dramatically down.