Sometimes it's hard to take everyday concerns seriously when you think about vanished ecosystems that existed 300 million years ago and were eradicated by giant explosions. My goals haven't changed, because my goal has always been to save the world!

I don't know if most people have truly taken on board what this says about our place in the natural world. It doesn't mean that humans are dominating the Earth, ruling over all of nature. In fact, it is a reminder that we are only a tiny part of nature, at the mercy of a system whose operations predate us by billions of years, and will continue billions of years after we're gone.

We have converted huge swaths of land and ocean into human habitats where we live and grow food and harvest energy. But there's been a sea change in the past century.

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.

I think it's the process of demystification, and realizing that we are not talking about some supernatural nightmare - we're talking about a natural process that the planet has gone through before, and which animals have survived before.

Some time ago we discovered the carbon cycle - a long-term set of chemical reactions that govern climates based on how much carbon is free in the atmosphere. At that point, it became clear that humans were affecting our environments far more profoundly than we realized. By releasing so much carbon and greenhouse gas into the environment, we're making long-term changes to every aspect of the natural world.

GMO agriculture will probably save the world in this century. But in the developed world, where few people are haunted by the specter of famine, people are free to fetishize heirloom tomatoes and worry about the provenance of what sits on their dinner tables.