Observational and model evidence together support wide-spread exposure to noncompensable heat under continued global warming

Abstract

As our planet warms, a critical research question is when and where temperatures will exceed the limits of what the human body can tolerate. Past modeling efforts have investigated the 35°C wet-bulb threshold, proposed as a theoretical upper limit to survivability taking into account physiological and behavioral adaptation. Here, we conduct an extreme value theory analysis of weather station observations and climate model projections to investigate the emergence of an empirically supported heat compensability limit. We show that the hottest parts of the world already experience these heat extremes on a limited basis and that under moderate continued warming parts of every continent, except Antarctica, will see a rapid increase in their extent and frequency. To conclude, we discuss the consequences of the emergence of this noncompensable heat and the need for incorporating different critical thermal limits into heat adaptation planning.

Global fertility in 204 countries and territories, 1950–2021, with forecasts to 2100: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

“…71 All of these aspects of climate change threaten food, water, and other resource security and dramatically increase the risk of heat-related illness and death. 71,[75][76][77][78] For example, the IPCC projects substantial declines in crop yields across many low-income settings due to climate change, including a 20-40% decrease in millet yield in the Sahel region in response to a potential 30-year mean increase of 2-3°C in maximum temperature. 79,80 Population growth will only worsen the growing strain on food supplies in this region in the future.…”