Deadly temperatures expected to arrive later this century are already here
Human beings have a superpower — sweating. When temperatures rise, beads of sweat exude from our pores and evaporate, releasing energy that cools the skin and keeps our bodies from overheating. This self-cooling mechanism has helped humans spread to every hot and humid corner of the globe. But that sweating superpower has a theoretical upper limit: When it gets too hot and humid, the laws of physics inhibit most sweat from evaporating from skin. That limit is hit when a bulb thermometer wrapped in a wet towel (a measure of heat and humidity known as “wet-bulb” temperature) reads 35° Celsius, or 95° Fahrenheit. Even the fittest human supplied with unlimited water would probably die after a few hours in these conditions. Scientists have thought that this temperature extreme occurs rarely, if ever, on Earth. But as the globe warms, wet-bulb temperatures around 35° C could become more common toward the end of the century in certain regions, endangering hundreds of millions of people, recent climate simulations suggest (SN:...