It's obviously tricky to convert cellulose to a useful biofuel. I think actually the most efficient way to use cellulose is to burn it in a co-generation power plant. That will yield the most energy and that is something you can do today.

I'm personally a moderate and a registered independent, so I'm not strongly Democratic or strongly Republican.

Facebook is quite entrenched and has a network effect. It's hard to break into a network once it's formed.

When people really understand it's do or die [and] if we work hard and pull through, it's going to be a great outcome; people will give it everything they've got.

I really do encourage other manufacturers to bring electric cars to market. It's a good thing, and they need to bring it to market and keep iterating and improving and make better and better electric cars, and that's what going to result in humanity achieving a sustainable transport future. I wish it was growing faster than it is.

An asteroid or a supervolcano could certainly destroy us, but we also face risks the dinosaurs never saw: An engineered virus, nuclear war, inadvertent creation of a micro black hole, or some as-yet-unknown technology could spell the end of us.

My opinion is it's a bridge too far to go to fully autonomous cars.