Climate-driven extreme heat may make parts of Earth too hot for humans. A study findings revealed that a rise of 2 degrees Celsius above preindustrial levels would subject the 2.2 billion inhabitants of Pakistan and India’s Indus River Valley, the one billion individuals in eastern China, and the 800 million residents of sub-Saharan Africa to prolonged periods of heat exceeding human tolerance each year.
This has already been happening in various places for a few years now. It’s just becoming more regular each year.
https://www.cnn.com/2021/07/17/opinions/deadly-heat-waves-wet-bulb-climate-change-ki-moon-verkooijen/index.html