[goatlover]

Mammals, reptiles and amphibians existed back then as well, as did a variety of plants. Uninhabitable sounds like most of the Earth turns into Venus, which won't happen. The current ecosystem will undergo change as some species adapt and thrive while others go extinct, migrate or are confined to smaller areas.

What this looks like for civilization and to what extent humans can mitigate is debatable. Climate models aren't civilization models.

[ben_w]

There's way too many options to put into even a book, let alone this message[0], but here are some things to consider:

• Burning all the known fossil fuels is more than enough to raise CO2 to the level necessary to severely impact (>25% slowdown) human cognition

• Although plants like CO2, they are often limited by other things instead

• Although we can build personal air supplies for us and greenhouses for plants to optimise each, this is more expensive than not causing the damage in the first place, so not doing the latter implies we will not do the former either

• We've messed up local environments more than once, and observed mass migrations as a result; while I'm fine with migrants and confused by those who aren't, I don't let my utopian ideals blind me to the political reality that this will end badly for many innocent people

• Quite a lot of property and infrastructure at low elevation and near the coast, combined with a significant risk that the threshold for total loss of various major ice sheets[1] is less than or equal to 4 C

[0] written 3h into a post flight cancellation queue for making it the airline's problem that I have work 2000 miles away in 5.5 hours and all the alternative flights they offer are booked out until a week tomorrow, so I apologise for anything weird in this comment

[1] I want to say Greenland, but I don't trust myself in this sleep-deprived state

[notacop31337]

Climate models might not be civilisation models, but climate has a very large role in the disruption of civilisation models, look at the Sumerians for evidence of climate/regional degradation and the impact that had on their civilisation. And mitigation is only one part of it, when shortages start, it's not just the climate you have to deal with, it's the humans, who are arguably far more vicious and erratic than any weather or climate.