Cities should function more like ecosystems, or even metabolisms. When we build, we should be thinking about how we can integrate into the ecosystems around us, but without sacrificing all the niceties of civilization like good restaurants, concert halls, and high-speed Internet access. I'm saying that partly tongue-in-cheek, but I'm also deadly serious. The future of technology is sustainable ecology.

I would want us to start our quest to survive mass extinction by rethinking how we build cities. Cities should be commonplaces of production, rather than consumption - they should be producing food, and fuel.

It's only been in the past two generations that we truly understood the impact our civilization has had on the natural world. To our credit as a species, we have turned this obscure scientific fact about carbon cycles into one of the most important political issues of the 21st century.

One reason that we're so adaptable is that humans are excellent tool users and homebuilders. When our environment doesn't provide us with something that we need, we try to make it ourselves out of whatever is available, whether that's rock or wood or ore or DNA.

Everything I had read in the fields of fiction and science led me to a single, dark conclusion. Humans are screwed, and so is our planet.

With enough money and international coordination, we can push incoming asteroids out of Earth's path. We might even be able to bring back extinct animals in the lab. The problem really isn't scientific - it's cultural. We aren't yet able to coordinate ourselves as a global civilization to do something simple like bring food to a famine-stricken region. We can actually use current satellite technologies to predict where famine will strike next, but we can't get food there - usually for political reasons.

Part of what I wanted to do in my book was point out that we have almost reached the point where we can prevent a mass extinction with the science and technology we have today. We can build carbon neutral cities.