I wanted to start visible a thread about ways to cope with the extreme heat

[NickB79]

80. Eventually, evaporation won't work anymore as the humidity climbs due to global warming

Beyond approximately 85% humidity, your body can't shed heat via evaporative cooling (ie sweating). At this point it doesn't matter how much water you drink; you still cook to death if you can't find cooler or drier conditions.

At the rate we're burning fossil fuels, it appears much of the planet will reach this threshhold in the next century or two: http://phys.org/news192206610.html

While the Intergovernmental Panel on Climate Change central estimates of business-as-usual warming by 2100 are seven degrees Fahrenheit, eventual warming of 25 degrees is feasible, he said.

"We found that a warming of 12 degrees Fahrenheit would cause some areas of the world to surpass the wet-bulb temperature limit, and a 21-degree warming would put half of the world's population in an uninhabitable environment," Huber said. "When it comes to evaluating the risk of carbon emissions, such worst-case scenarios need to be taken into account. It's the difference between a game of roulette and playing Russian roulette with a pistol. Sometimes the stakes are too high, even if there is only a small chance of losing."

Steven Sherwood, the professor at the Climate Change Research Centre at the University of New South Wales, Australia, who is the paper's lead author, said prolonged wet-bulb temperatures above 95 degrees would be intolerable after a matter of hours.