Some heat in July: ‘virtually impossible’ without climate change, analysis says

Some of the extreme temperatures recorded in the southwestern United States, southern Europe and northern Mexico earlier this month would have been “virtually impossible” without the influence of man-made climate change, according to research slated for publication Tuesday.

During the first half of July, hundreds of millions of people in North America, Europe and Asia experienced intense heat waves.

According to the researchers, the probability of a heat wave in China is 50 times higher due to climate change.

Fire in Nueva Peramos, Greece, on July 19. Photo Louisa Gouliamaki/Agence France-Presse – Getty Images

World Weather Attribution, an international group of scientists who measure the extent to which climate change influences extreme weather events, focused on the worst heat on record to date during the Northern Hemisphere summer.

In the United States, temperatures in Phoenix have reached 43 Celsius or higher for more than 20 days in a row.

Many places in southern Europe are seeing record triple-digit temperatures. A remote township in China’s Xinjiang region reached 52.2 degrees, breaking the national record.

“Without climate change, we wouldn’t see any of this,” says Friederike Otto, professor of climatology at Imperial College London and co-founder of World Weather Attribution.

“Or it would be so rare that it basically wouldn’t be happening.”

But in a climate disrupted by fossil fuel emissions, heat waves of this magnitude “are not rare events,” he said.

Before the Industrial Revolution, North American and European heat waves were virtually impossible, according to the researchers’ statistical analysis.

China’s heat wave would only have occurred about once every 250 years.

If the composition of the atmosphere remained at current levels, the United States and Mexico could expect heat waves like the one this month about once every 15 years.

In southern Europe, every year there would be a 1 in 10 chance of a similar event occurring.

In China, there would be a 1 in 5 chance each year.

But as humans continue to burn fossil fuels and emit greenhouse gases into the atmosphere, the odds will continue to tilt in favor of extreme heat.

Even if we stop doing it, temperatures won’t get colder again, they’ll just stop rising.

“We have to live with the heat waves we see now,” says Otto.

With temperatures rising in Europe, Greece has faced a wave of wildfires that have forced the largest evacuations in the country’s history.

The scorching heat has made firefighting efforts difficult, according to authorities.

According to a recent study, the increased frequency and intensity of forest fires in the Mediterranean may also be related to climate change.

“The heat increases the risks,” said Julie Arrighi, director of the Red Cross Red Crescent Weather Center and one of the World Weather Attribution researchers.

“It is mortal”. Arrighi insisted on the need to adapt cities and critical infrastructure to extreme heat while reducing greenhouse gas emissions.

Many local and national governments, especially in Europe, have created heat action plans that include things like public refrigeration centers and early warning and coordination between social services and hospitals.

But even where these programs exist, they are imperfect and, for now, the human cost of extreme temperatures remains high.

The death toll from heat this month won’t be clear for some time, but more than 100 people have already died this summer in Mexico from heat-related causes, according to the National Health Secretariat.

Last summer, approximately 61,000 people died in Europe from heat waves, according to another recent study.

The World Weather Attribution study on heat waves was not peer-reviewed, but the results were based on standardized methods published in 2020.

The group uses more than a dozen climate models to compare real-world observed temperatures with modeled projections of the planet without human-caused climate change.

“This methodology is very common in this field,” said Andrew Pershing, vice president for science at the nonprofit Climate Central.

Pershing was not involved in Tuesday’s study, but has collaborated with World Weather Attribution in the past.

The enormous heat that much of the planet is experiencing is “shocking” in a historical context, Pershing said, but added that the conclusions about the role of climate change “are not surprising.”

The first two weeks of July were probably the hottest on Earth ever recorded, according to an analysis by the European Union’s Copernicus Climate Change Service.

The National Oceanic and Atmospheric Administration forecasts more unusually warm temperatures across most of the United States in August.

c.2023 The New York Times Company

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