UCLA Study: Duration of Heat Waves Accelerating Faster Than Global Warming

While millions of Americans swelter under heat warnings from the National Weather Service, new research finds that not only will climate change make heat waves hotter and longer, but the lengthening of heat waves will accelerate with each additional fraction of a degree of warming, UCLA announced Tuesday.

In the study published Monday in the journal Nature Geoscience, researchers led by UCLA and the Universidad Adolfo Ibañez in Santiago, Chile, found that the longest heat waves will see the greatest acceleration, and the frequency of the most blistering heat waves will increase the most.

The duration of a heat wave exacerbates the risk to people, animals, agriculture and ecosystems.

By incorporating variables into climate models that account for how each day’s temperature influences the temperature of the following day, the researchers detected this acceleration at a global level, scientists determined.

The equation they developed has the flexibility to analyze one region or to gain additional insight by analyzing multiple regions as a whole, said senior author and UCLA climate scientist David Neelin.

“Each fraction of a degree of warming will have more impact than the last,” said Neelin, a professor of atmospheric and oceanic sciences who studies climate variability. “The acceleration means that if the rate of warming stays the same, the rate of our adaptation has to happen quicker and quicker, especially for the most extreme heat waves, which are changing the fastest.”

People have already begun feeling longer heat waves in recent decades, Neelin noted. Just this month, a late-June heat dome settled over much of the United States, breaking daily heat records, damaging a Virginia drawbridge and causing heat-related illness among dozens at a high school graduation.

Europe sweltered through the first week of July as scorching heat closed the Eiffel Tower, Wimbledon launched “Operation Ice Towel” for its record hottest opening day, and the Acropolis in Athens, Greece, was temporarily shuttered. The extreme heat has been blamed for hundreds of deaths.

Parts of 18 states across the country were under heat advisories Tuesday, including extreme heat warnings in California, Arizona and Nevada, where temperatures could hit 120 degrees.

“We found that the longest and rarest heat waves in each region — those lasting for weeks — are the ones that show the greatest increases in frequency,” said Cristian Martinez-Villalobos, the study’s lead author and an assistant professor of engineering and science at the Universidad Adolfo Ibáñez. “By taking into account the natural variation of temperatures at each location, we find that recent observed trends of heat wave durations already follow a similar pattern of acceleration predicted by climate models.”

Future research is dependent on federal budgets, Neelin said.

“Deprioritizing and defunding climate and science research will limit our capacity to make region-specific projections for risk management,” he said. “Without that, we’ll have much less ability to adapt to climate change at the very time when we need to accelerate adaptation planning.”