Carbon tax has the advantage of basically being able to subsidize one set of activities that you want with another set of activities that you don't want. It's like a cigarette tax.

One advantage of a solar collector in space: It would be some kind of origami thing that would unfold and be relatively light because it doesn't have gravity to deal with.

When the government tries to run innovation, sometimes it does it well and sometimes it doesn't. So setting up a situation where the market runs innovation, which is a cap-and-trade idea, may well have more flexibility.

Many of my contemporaries in the developed world see subsistence farming as soulful and organic, but it is a poverty trap and an environmental disaster.

We are as gods and might as well get good at it.

There's no unemployment in squatter cities. Everyone works. One-sixth of humanity is there. It's soon going to be more than that.

Do what's good for humans, modeled on how humans already do things; ignore what's convenient for computers.