In many places, humans have adapted to live on the verge of the survivable wet bulb temperature. These places have been relatively static in temperature and hum

In many places, humans have adapted to live on the verge of the survivable wet bulb temperature. These places have been relatively static in temperature and humidity for hundreds of years and while they may have occasional spikes, it's something mitigatable. Climate change means longer and higher extremes, and if an area exceeds the wet bulb temperature then that means any sort of outside work or function is actively deadly.