Record-Breaking Summer Heat Could Happen Every Year, Study Predicts

Jun 14, 2016

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It’s going to be a hot next few weeks in Louisville, with temperatures projected to reach the upper 80s or 90s almost every day.

Flavio Lehner says to get used to it.

Lehner, a post-doctoral researcher at the National Center for Atmospheric Research, is the author of a study on summer temperature projections. Using climate forecasting data, he and his colleagues found that if carbon dioxide emissions continue on their current pace, it’ll translate to hotter summers for most of the globe.

“Towards the end of this century, under a scenario where we continue emitting greenhouse gas unabated, you will see a very large chance that basically every summer in most parts of the world will be as hot or hotter than the hottest we’ve seen up to date,” Lehner said.

For the years 2061-81, the probability that any summer would be record-setting is about 80 percent, Lehner said, though for some areas, it’s higher. Under another scenario, where greenhouse gas emissions are reduced, the probability drops to 41 percent.

Lehner said that’s the silver lining of the study.

“Obviously, we found an uncomfortable and very high risk of seeing these very hot summers on a regular basis in the future,” he said. “But we also saw that by mitigating some of this warming by reducing emissions, we could actually show that in particular regions where a lot of people live, those regions can see a strong reduction of this.”

He noted that the “greenhouse gas reduction” scenario he used is a pretty moderate scenario, and one that wouldn’t even limit the planet’s warming to 2 degrees Celsius. That’s the limit many scientists are advocating. But the summer heat benefits of these potential emissions cuts wouldn’t be spread evenly.

Instead, Lehner found that some areas — including the U.S. East Coast — would still have a 90 percent chance of being as hot or hotter than record summers, even if carbon dioxide emissions are reduced. But there will be substantial benefits in places like Brazil, central Europe and eastern China.

Besides making some areas of the Earth very uncomfortable in the summer, Lehner said such high temperatures would likely affect agriculture and health.