Genuine question:

What human population could a +4C world support?

— Richard Lawson (@DocRichard) August 19, 2020

I think about 100-300 million, but certainly not greater than a billion. Since a +4C world seems about what we’ll hit, I’d say by 2200 if we don’t completely apocalypse ourselves (also very likely, due to nuclear war), there will be 300 million people alive on earth.

If we do nuke ourselves (I give this a 60% chance), possible extinction, but I’d say 2-3 million alive on earth as most likely, with about 50/50 chance of extinction.