Days of 100-degree heat will become weeks as climate warms, U.S. study warns

(Inside Climate News, 17 Jul 2019) Even regions of the U.S. where extreme heat and humidity have been rare should expect significant increases in the number of hot days by mid-century.

Nearly every part of the United States will face a significant increase in extremely hot days by mid-century, even if some action is taken to reduce greenhouse emissions, a new study says. If nothing is done to rein in climate change, it warns, the impact will be worse.

Large parts of the Central and Eastern U.S. will get a taste of what that feels like over the coming days as a muggy heat wave settles in.

The study, published in a peer-reviewed journal and as a longer report by the Union of Concerned Scientists, used 18 climate models to predict changes in the heat index—the mix of heat and humidity that reflects how hot it feels—across the contiguous U.S. as global temperatures rise over the coming decades.

It found that the number of days when the average temperature will feel like 100 degrees in the Lower 48 states will more than double, from about two weeks at the end of the last century to 30 days by mid-century, even with some efforts to reduce the greenhouse gas emissions that drive global warming.

And the number of days with a heat index of 105°F or more will more than triple to nearly three weeks, the study found.

External link

Inside Climate News, 17 Jul 2019: Days of 100-degree heat will become weeks as climate warms, U.S. study warns