(This was a Twitter thread)
There are very few examples on planet in human history where human societies or civilizations completely vanished. Even in times of catastrophic change–creation of the Sahara, 90% fatal pandemics in Amazon, volcanic devastation–human beings have stayed, even if reduced from large scale societies to hunter gatherer bands. Society changes, civilizations collapse, but the species does not go extinct. Indeed, our very evolution has been achieved by dealing with continuous stress and change including population crashes to as few as one thousand or less individuals for the entire species for as long as 100,000 years. We survived, evolved and thrived under extraordinary pressures that would have driven most species–indeed all other hominid species–to extinction. We are extraordinarily adaptable and virtually everything about us is designed to allow us to survive under extremely stressful conditions. That’s why we are here and not a single other human species remains. Society, culture, civilization are all dispensable, it is our extended family that is the default unit that allows Homo sapiens to survive almost anywhere under any conditions. The point of this is that no matter how severe climate change is, no matter if civilization collapses and our numbers are reduced to 1/100,000,000th of today’s population, Homo sapiens will survive. It would take something much more drastic–a giant asteroid, perhaps, or a nuclear war involving thousand of warheads–to completely annihilate the species forever. Both of which are possible, of course. But we will survive even the worst case global warming. It will not be comfortable, the impact on nearly all the world’s ecosystems will be devastating, and it’s hard to imagine a more dystopian future, but it will be livable for just enough of us to keep the genome going.