Not only that, but +4℃ is also when megafauna - any species over 45Kg (100lbs) - start to go extinct.
And that includes humans.
At that point, we’re looking at our global population free-fall cratering into the 1-2B range over 1-3 decades, at best. Worst-case is under 500M, with a full reversion back to the Bronze Age or earlier. And a continuing persistent (slower) decline down to a big fat zero.
Not mentioned: if you added 5 C to this bit of history - https://en.wikipedia.org/wiki/2021_Western_North_America_hea... - things could get pretty grim in BC.
Wouldn't you have to subtract out the warming to date and add that difference rather than 5 on top?
Not only that, but +4℃ is also when megafauna - any species over 45Kg (100lbs) - start to go extinct.
And that includes humans.
At that point, we’re looking at our global population free-fall cratering into the 1-2B range over 1-3 decades, at best. Worst-case is under 500M, with a full reversion back to the Bronze Age or earlier. And a continuing persistent (slower) decline down to a big fat zero.
[dead]