Published July 25, 2023 at 6:51 a.m. ET
People walk through cooling misters along the Las Vegas Strip, July 13, 2023, in Las Vegas. (AP Photo/John Locher, file)
The fingerprints of climate change are visible everywhere in the intense heat waves that have hit the planet this month, according to a new study. Researchers say the deadly heat waves in the southwest United States and southern Europe could not have happened without the continued buildup of warming gases in the air.
These unusually strong heat waves are becoming more frequent, according to the study published on Tuesday. The same study found that increases in heat-trapping gases, largely from burning coal, oil and natural gas, made another heat wave – the one in China – 50 times more likely, with a risk of occurring approximately every five years. .
A stagnant atmosphere, warmed by carbon dioxide and other gases, also made Europe’s heat wave 4.5 degrees Fahrenheit (2.5 degrees Celsius) hotter, those in the United States and Mexico 3 .6 degrees Fahrenheit (2 degrees Celsius) and that of China. a toaster at 1.8 degrees Fahrenheit (1 degree Celsius), according to the study.
Several climatologists, using tree rings and other surrogates for temperature records, say this month’s heat is likely the hottest Earth has seen in about 120,000 yearsby far the hottest in human civilization.
“If there had been no climate change, such an event would almost never have happened,” said the study’s lead author, Mariam Zachariah, a climate scientist at Imperial College London. She called heat waves in Europe and North America “virtually impossible” without the increase in heat starting in the mid-1800s. Statistically, China’s could have happened without global warming.
Since the advent of industrial-scale burning, the planet has warmed by 2.2 degrees Fahrenheit (1.2 degrees Celsius), so “they are not uncommon in today’s climate and the role of climate change is absolutely overwhelming,” said Friederike Otto, a climatologist at Imperial College. who leads the World Weather Attribution team of international volunteer scientists who carry out these studies.
The particularly intense heat waves currently experiencing Texas, California, Arizona, New Mexico, Nevada, Baja California, Sonora, Chihuahua and Coahuila are likely to occur approximately once every 15 years in the current climate, according to the study.
But the climate is not stabilized, even at this level. If it’s a few more tenths of degrees, this month’s heat will become even more common, Otto said. Phoenix experienced a record 25 consecutive days of temperatures at or above 110 degrees Fahrenheit (43.3 degrees Celsius) and more than a week in which the nighttime temperature never fell below 90 degrees Fahrenheit (32. 2 degrees Celsius).
In today’s climate, heat in Spain, Italy, Greece and some Balkan states is likely to recur every decade, the study found.
Because weather attribution researchers began their analysis of three simultaneous heat waves on July 17, the results have not yet been peer-reviewed, which is the gold standard of science. But the team used scientifically valid techniques, the team’s research is regularly published, and several outside experts told The Associated Press it made sense.
The way scientists perform these rapid analyzes is to compare observations of current weather in the three regions to repeated computer simulations of “a world that could have done without climate change,” said co-author Izidine Pinto. of the study and climatologist at the Royal Nederland. Meteorological Institute.
In Europe and North America, the study does not claim that human-caused climate change is the sole cause of heat waves, but it is a necessary ingredient because natural causes and chance could not. not alone produce this phenomenon.
Texas State Climatologist John Nielsen-Gammon said the study was reasonable, but it covered a large area of the southwestern United States and therefore may not be applicable at all locations in the region.
“In the United States, it is clear that the entire southern tier is going to see the worst of the ever-worsening heat and this summer should be considered a serious wake-up call,” said Jonathan Overpeck , dean of environment at the University of Michigan.
With heat waves, “the most important thing is that they kill people and they especially kill, injure and destroy the lives and livelihoods of the most vulnerable people,” Otto said.
——
Associated Press climate and environment coverage receives support from several private foundations. Learn more about AP’s climate initiative here. The AP is solely responsible for all content.