We will move to a low-carbon world because nature will force us, or because policy will guide us. If we wait until nature forces us, the cost will be astronomical.

We will move to a low-carbon world because nature will force us, or because policy will guide us. If we wait until nature forces us, the cost will be astronomical.

We're going to get to the point where we ask how the hell we put up with high carbon for so many years. You thank your lucky stars, because you are seeing this transformation in your lifetime. You are going to tell your children and your grandchildren you saw this whole thing in front of your eyes.

We are just about to cross the 400 parts per million threshold.

You can rear children in an antagonistic environment or in a facilitative one with a good combination of love and discipline. It's about supporting them, and recognizing achievements and contributions, but also saying, "that's fantastic but it's not enough, here's the next thing."

The fact that solar has gone down 80 percent since 2008 is astonishing. Wind is perhaps not coming down as quickly. Lack of storage - batteries - is a bottleneck. That makes it very difficult to put large amounts of renewable energy on the grid.

When you have a vision of where you need to go, it sounds utopian. But when you get to the tipping point, your understanding switches.