New analyses find that warming is fueling severe hot spells on both sides of the Atlantic this summer, spurring warnings about the need to guard against increasingly dangerous heat.

On Friday, close to half of Americans will endure heat made three times more likely by warming, according to a report from Climate Central. Heading into the weekend, extreme heat will bear down on the Rocky Mountains, the Great Plains, and much of the Southeast, with high humidity sending the heat index, an indicator of how hot it feels, above 110 degrees F (43 degrees C) in some parts.

The U.S. hot spell follows a heat wave that settled over southern Europe in July, when temperatures topped 104 degrees F (40 degrees C) in parts of Spain and the Balkans. A new analysis from World Weather Attribution finds the heat would have been “virtually impossible if humans had not warmed the planet by burning fossil fuels.”

Heat has proved especially dangerous in Europe, though estimates of heat deaths vary significantly. Official records tend to undercount such deaths — a heart attack prompted by a hot spell will be recorded as a heart attack, not a heat death. Scientists can infer how many people are actually killed by heat by tallying the number of excess deaths during hot periods, though methods differ. According to one study, which gauged the effect of even modest warmth, heat has killed more than 175,000 people in Europe each year, on average, since 2000.

The World Health Organization warned this week that heat deaths are set to rise in Europe as the planet warms. “Extreme heat is a problem particularly for elderly people, especially those living alone,” said Hans Kluge, European regional director for the WHO. “It can also place an additional burden on pregnant women.” He stressed the need to care for vulnerable people, protect outdoor workers, and stem warming.

The period from July of 2023 through June of 2024 measured 1.5 degrees C warmer than the preindustrial era, meaning the world has at least temporarily surpassed the temperature target set forth in the Paris Agreement.

Sourse：https://e360.yale.edu/digest/climate-change-heat-wave-europe-america