By SETH BORENSTEIN AP Science Writer
KENSINGTON, Maryland (AP) — The contiguous United States sizzled to its hottest month ever last month, according to the National Oceanic and Atmospheric Administration.
July averaged 76.89 degrees Fahrenheit (24.94 degrees Celsius) across the Lower 48 states, eclipsing the Dust Bowl’s July 1936 by an eighth of a degree. Records go back to 1895.
“It’s not good when you’re breaking records from the Dust Bowl, which we are in this case,” said meteorologist Jeff Masters of Yale Climate Connections. “And that was a crazy sort of situation where you put tens of millions of people in motion. You had this great migration because of the drought and the heat that hit the center of the U.S. — just a cataclysmic event in U. S. history. If we’re exceeding records from The Dust Bowl, that says that we’re in deep trouble.”
Although it was unusually cool in Alaska, hotter-than-normal conditions blanketed the Lower 48, with the most excessive heat in the Mountain West, Southwest, Northern Plains and Southeast. The heat was so widespread that every one of the Lower 48 states was at least 1 degree Fahrenheit (nearly 0.6 degrees Celsius) warmer than the 20th century average, said Russ Vose, chief of monitoring at NOAA’s National Center for Environmental Information.
The heat in the Dust Bowl years was more concentrated in parts of the Midwest and was aggravated by agricultural practices at the time, Vose said.
What’s happening now is due to the burning of coal, oil and gas, scientists said.
“Extremely high temperatures across the continental U.S. this summer, along with intense drought and fire conditions, are absolutely consistent with the climate change signal,’ said Katharine Jacobs, a climate scientist at the University of Arizona.
The biggest driver of the record heat was nighttime lows that smashed the old mark for hottest minimums by 0.7 degrees, NOAA said. Hotter nights are a classic sign of human-caused climate change, according to scientists and several studies in peer-reviewed literature. NOAA’s calculation is based on averaging 24 hours of temperature, not just highs or lows.
“If you’re talking heat waves, that nighttime low is incredibly important for determining total heat stress,” Masters said. “So if it doesn’t cool off at night, your body doesn’t have time to readjust to all the heat.”
As nighttime temperatures increase, more people die and lose sleep, studies show.
The years 2021 and 1936 tie for America’s hottest summer, which is June through August. Through July, 2026 is a shade cooler than 2021, which was powered by record heat in June.
Because of climate change, Masters said, “this may be one of the coolest years we’re gonna experience for the rest of our lives.”
What’s needed, Masters said, is “to stop burning so many fossil fuels. We also need to be spending money to adapt to the new climate that we’ve put in place.”
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