We are headed to a radically new Earth, at least from our perspective. But from the planet's perspective, this is nothing new. As the geologist Peter Ward is fond of pointing out, we are actually heading back to a time kind of like the Miocene. The Miocene ended about 5.5 million years ago, and it was the last time that the planet had no icecaps.

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 think small animals can escape from many kinds of natural disaster more easily. There are just more places for them to hide, and more ways for them to find safe habitats. So this means that rats are set up to rule the Earth, but most of us already knew that. Now you know why.

Survivor species tend to have huge populations, so they can afford to lose many individuals and still survive as a species. They also tend to be small. If you're small, you need less food - which is great in a situation where famine is everywhere.

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.

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.

Amphibians are dying out like crazy, and frogs and salamanders may be largely extinct by the end of the twenty-first century. Imagine an animal that begins its life in the water, but ends it on land - already, that's pretty weird. But, also, a lot of them are incredibly tiny and look wildly improbable. They have funny little toes, they stretch their throats into weird bubble shapes when they croak, and some of them are poisonous to the touch. I think kids from the twenty-second century might mythologize amphibians the way kids today mythologize dinosaurs.