Heat waves could last longer and spread farther even with steep emissions cuts, models suggest

Some future heat waves could last nearly half a year, even with steep cuts in planet-warming pollution, according to new research examining extreme heat across multiple regions.

Here's what to know

In a study published this month in Nature Communications, researchers led by Philipp Aglas-Leitner of Freie Universität Berlin compared past heat waves with climate-model projections. The team examined both futures modeled with sharp emissions reductions and those with very high emissions.

Even under sharp pollution reductions, some modeled heat waves lasted nearly six months or a full six months in Europe, South America, northeast Siberia, the Pacific Northwest, and North Africa and the Middle East, according to Earth.com's coverage of the study.

The concern is that, even with steep cuts in emissions — which may not necessarily be on the horizon — future extreme heat events could make today's already disruptive events look tame.

What's being done?

The Paris Agreement provides a framework for limiting warming. However, the study found substantial heat risks even at its upper limit of 3.6°F (2°C). At that level of warming, almost 20% of projected heat waves in Europe would surpass the most intense day of a benchmark 2018 event, according to Earth.com.

The warming expected under countries' climate pledges is approximately 4.7°F to 5°F (2.6°C to 2.8°C), according to the U.N.'s 2024 Emissions Gap Report. Near that level, the share of projected European heat waves exceeding the 2018 peak was 27% to 37%, Earth.com explained.

The researchers called for adaptation measures to help communities prepare for extreme heat. They identified the speed of adaptation and the timing of heat waves as factors shaping damage, while emphasizing the human body's limits for heat tolerance. 

"Without substantial emission reductions and consistent adaptation measures, however, a significant part of the 21st century will be defined by heat that goes far beyond our recent experiences," Aglas-Leitner said in a university press release.

Where can I learn more?

The prospect of monthslong heat waves comes as extreme heat is already stretching beyond historically warmer seasons: 

• Extreme heat is spilling into spring and autumn across more than half the world.

• Overlooked climate feedbacks could make planetary warming 30% worse by the end of this century.

• Western Europe's record heat killed at least 35,000, prompting WHO warnings about future extremes.

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