> If you want to think of a way it could be possible, though, think of those areas that would be habitable, realize that they would be highly contested, are mostly presently permafrost, and consider your own ability to both protect and survive on melted tundra and reproduce there, given you will starve in a single season without food.
I actually did consider that first - that maybe at +8c humans will kill each other, but that's just pure speculation.
And, sure, food is necessary daily and constantly, but the situation you outline isn't an overnight thing. Hell, it isn't even a 100-year change, +8c is a lot longer.
That gives you plenty of time to move, and at +8c, as long as it is stable at +8c, you'd still have enough arable and livable land to ensure that humanity is nowhere close to extinction.
So if it isn't lack of land, and it isn't the temperature range that causes human extinction, what does?
I think it is incredibly unlikely personally. We have evolved nearly beyond environmental dependence, certainly beyond local environmental problems, and it is difficult to imagine our extinction as long as there are some plants and insects that survive. Possibly we could even persist on algae farming.
But if you add the fact that antibiotics will be in short supply, novel zoonotic diseases will ramp up, and most knowledge of how to survive in the wild has been lost and probably can’t be reconstituted in a couple of violent generations, I can see how it could come about.
There is also the social and psychological impacts of that scale of loss, and there are some other sort of scary indicators you could lean on (Calhoun rat experiments) to indicate that there are limits to what animal populations will reproduce through.
I’m not worried about it — we seem like a pretty robust system from my perspective. But it is interesting to think about abstractly.
I actually did consider that first - that maybe at +8c humans will kill each other, but that's just pure speculation.
And, sure, food is necessary daily and constantly, but the situation you outline isn't an overnight thing. Hell, it isn't even a 100-year change, +8c is a lot longer.
That gives you plenty of time to move, and at +8c, as long as it is stable at +8c, you'd still have enough arable and livable land to ensure that humanity is nowhere close to extinction.
So if it isn't lack of land, and it isn't the temperature range that causes human extinction, what does?