Human extinction, or not.

(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.

Permian extinction

Here I am watching UCTV again. I love UCTV. It’s basically lectures by people smarter than me. Sometimes I understand them. The linguists, the historians, this paleontologist showing funny slides of the Burgess Shale. He’s talking about the Permian extinction, at the dawn of the Triassic. He says that 96% of all species disappeared. That I knew. This is what they can deduce from the fossil record, all the extraordinary variety of life in the Permian was reduced to virtually nothing as the Triassic began. But then he said that it appears that the mega-extinction occurred in a span of two hundred thousand years. That I did not know. I had heard millions of years, even low millions, but two hundred thousand years? He reeled off the theory, the evidence, the processes of annihilation involved, and how they came out to around 200,000 years. That is fast. It may not seem fast to us–language itself may only be two hundred thousand years old–and four generations of people living to the limits of human life expectancy, from the birth of the great grandmother to the death of the great granddaughter, barely stretches two hundred years. But in the expansive span of evolution and even greater expanse of geologic time, two hundred thousand years is less than a minute in a day. It’s almost instantaneous. Annihilation, when it happens en masse, happens suddenly. Apparently one of the few therapsids–a mammal like reptile, closer to us than to dinosaurs–survived, which was good for us, otherwise I wouldn’t be here writing this and you reading it or doing any homo sapien things. And we’ll end this thus, otherwise it will be a book.