Since then when the lah-di-dahs start defining denial of climate science down (more on that later after everybunny else has chewed it to death), Eli points out that there is a real end game out there, that humans cannot survive when wet bulb temperatures go over 37 C because the heat engine that they am (Eli is a bunny) gets stuffed. Moreover if this starts happening a few days a year, why by gosh and golly, folk will pick up and move and some of those folk have nuclear weapons, so it will not be all peaches and cream.
Now comes a report looking at this issue in the US of A and reported on by Tom Randall at Bloomberg News. "Risky Business" looks at the effects of business as usual and points out that large areas of the US will have a few such days each year by 2100 and by 2200, the Midwest will have to move elsewhere to survive more than a month of hell. That or die.
It is interesting to compare the map from Risky Business to that from Sherwood and Huber for a high CO2 world.
We conclude that a global-mean warming of roughly 7 °C would create small zones where metabolic heat dissipation would for the first time become impossible, calling into question their suitability for human habitation. A warming of 11–12 °C would expand these zones to encompass most of today’s human population. This likely overestimates what could practically be tolerated: