The early Triassic was a period when the planet was recovering from the worst mass extinction it had ever known - that was the end Permian extinction, where climate change caused in part by mega-volcanic eruptions wiped out ninety-five percent of life on Earth. It took about ten or twenty million years for the planet's ecosystems to stabilize. During that time you saw a lot of weird, out-of-balance ecosystems where, for example, crocodile-like predators ripped the crap out of each other along the coasts.

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.

Even though I now know that it's likely the Earth will suffer through mega-volcanoes or meteor strikes that could take out millions or billions of people, I feel less anxious about it because I actually understand what the threats are. There's nothing like researching something exhaustively to make it less terrifying.

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.

Humans are a great survivor species but our survival will be pretty grim if all of the plants and animals we depend on die out. That's why any human survival strategy has to include a plan to maintain our environment roughly in the state that it's in now.

The fact is that humans have been shaping the genetics of what they eat for thousands of years. Genetic engineering simply speeds up the process that used to take generations. Preventing people from getting things like golden rice or disease-resistant cassava destroys human life, and does not spare the environment in any way.