On hot and humid summer days, our bodies are less able to cool themselves due to the moisture in the air around us. Joseph Stromberg explains the impact this might have as the planet warms:
According to a study published yesterday in Nature Climate Change, increased heat and humidity has already reduced our species’ work capacity by 10% in the warmest months, and that figure could rise to 20% by 2050 and 60% by the year 2200, given current projections.
The Princeton research team behind the study, led by John Dunne, came to the finding by combining the latest data on global temperature and humidity over the past few decades with American military and industrial guidelines for how much work a person can safely do under environmental heat stress. …
[T]hinking about how the study defines “work” can lead to a troubling conclusion: in 2100, throughout much of the U.S., simply taking an extended walk outdoors might not be possible for many people. The economic impacts—in terms of construction and other fields that rely upon heavy manual labor—are another issue entirely. Climate change is certain to bring a wide range of unpleasant consequences, but the effect of humidity on a person’s ability to work could be the one that impacts daily life the most.
Lauren Morello provides some comparisons:
The combined heat and humidity in Washington, D.C., would be more stressful than conditions in today’s New Orleans. New Orleans, in turn, would experience more heat stress than Bahrain does now. And in Bahrain — an island in the Persian Gulf where temperatures already hit 120°F in summer months — heat stress would creep close to the limit that humans can endure for more than a few hours at a time.