That said, a lot of people buy products with "green" in the brand name, but make no attempt to understand what it would really take to live sustainably. I think one of the most pernicious examples of magical environmental thinking is the anti-GMO movement.

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.

I try to be realistic and pragmatic. I have a lot of hope for humanity as a species, but obviously as individuals we can be extremely flawed. We may have to go through some very terrible times in the near future, even if we ultimately survive as Homo sapiens.

So science alone cannot solve this problem [mass extinction of humans]. It's something that we can only tackle by bringing science together with culture, economics, and even politics.

I think that humans are also set up to survive. We're not as small as rats, but we make up for that by being intelligent enough to make our own hiding places and to adapt to new habitats, even if they are changing very quickly. We have an enormous population, and can afford to lose billions of people without suffering very much as a species. Indeed, some would say losing five billion people would be good for the planet - I disagree with them, but can't deny that we would do just fine if there were two billion of us or even one billion.

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.

If we return abruptly to a Miocene-like climate, it's reasonable to think that we would experience a lot of extinctions, and maybe even a mass extinction in the long term. Would the life on Earth be radically different? Of course we can't say for sure, but I think a lot of it would look familiar. Like a lot of people, I worry a lot about whether marine mammals would survive, especially whales. Ocean acidification is one of the major killers in climate change events, and that makes the ocean a very inhospitable place.