Our research shows that the footprint of life-altering heat using updated, empirically derived heat stress limits is vastly expanded. The additional regions most significantly affected are projected to be the equatorial and Sahel regions of Africa and eastern China given future warming scenarios that reach upward to 2 °C, a viable outcome by the end of the century, perhaps sooner, without drastic reductions in greenhouse gas emissions (31). Continued warming above 3 °C and 4 °C, respectively, causes North and South America, as well as northern Australia, to experience extended periods of dangerous heat.

Greatly enhanced risk to humans as a consequence of empirically determined lower moist heat stress tolerance