Is the Earth really too hot for humans to survive?

Many countries have experienced extremely hot weather recently, but most of the inhabited world will never be "too hot to live", especially in relatively dry climates. When it's hot outside in dry places, most of the time our body can cool itself by evaporating water and heat from the skin in the form of sweat.

However, there are places where it is sometimes dangerously hot and humid, especially where there are hot deserts right next to a warm ocean. When the air is humid, sweat doesn't evaporate as quickly, so sweating doesn't cool us down like it does in drier environments.

In parts of the Middle East, Pakistan and India, the summer heat can combine with the humid air that blows in from the sea, and the combination can be downright deadly. Hundreds of millions of people live in these regions, most of whom do not have access to indoor air conditioning. (Scott Denning, Colorado State University, more at theconversation.com)