Europe has had five 500-year summers in 15 years. And now this.

A continent without air conditioning struggles with 100-degree days in June—and wonders how it will cope with the hotter years ahead.

BY STEPHEN LEAHY, National Geographic, June 28th, 2019

Another deadly heat wave has Europe in its sweaty grip this week. Record temperatures topped 100 degrees Fahrenheit (37.8 degrees Celsius) in parts of France, Germany, Poland and Spain, with hotter days to come. The same thing happened last year—record-breaking heat was responsible for 700 deaths in Sweden and more than 250 in Denmark, countries that have never needed air conditioning before this new era of climate-change-driven extreme events.

Europe’s five hottest summers in the past 500 years have all occurred in the last 15 years, not including this summer. All have been deadly. The 2003 heat wave was the worst, having led to the deaths of over 70,000 people; in 2010, 56,000 died in Russia alone.

These extreme heat events are all connected to a slower jet stream that locks weather systems into place, says Michael Mann of Penn State University. Mann co-authored a study last year that linked the slowdown in the jet stream—the band of high-altitude winds that sweep around the globe from west to east—to last summer’s unprecedented droughts, heat waves, wildfires, and flooding events across the entire Northern Hemisphere. And it is likely behind India’s weak monsoon rains and the widespread flooding in the U.S. Midwest this year.

“My colleagues at PIK (Potsdam Institute for Climate Impact Research) have verified that this is what we’re seeing right now in Europe,” Mann said in an email.

Read more about the heat waves in Europe