Climate study says ‘record-breaking’ heat is becoming more likely to change climate تغير

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Research indicates that “record-breaking” heat waves, worse than those that recently hit the Northwest, are expected to become more likely in the future. The study is a stark new warning about the rapidly escalating risks posed to lives by the climate emergency.

Scientists said the shocking temperature extremes experienced in the Pacific Northwest and in Australia 2019-2020 were “exactly what we’re talking about”. But they said the world has yet to see anything close to the worst possible impacts, even with global warming that has already occurred.

The research found that densely populated areas of North America, Europe and China are the areas where standard extremes are most likely to occur. One illustrative heat wave produced by computer models used in the study showed that some locations in central North America had temperatures that were 18°C ​​above average.

Scientists said that preparing for such unprecedented extremes is vital, as they can cause thousands of premature deaths, and that measures taken to adapt to date have been based solely on past temperature records.

Scientists already know that heat waves of the kind we see today will become more common as the climate crisis develops. But heat waves are usually analyzed by comparison to the past, which means that the vast majority are marginally hotter than before. This can give a false sense of a gradual rise in standard temperatures.

Instead, the new computer modeling study looked for the first time at the highest margins by which heatwave records could be broken a week into the future.

He found that heat waves that broke previous records by about 5 degrees Celsius will become two to seven times more likely in the next three decades and three to 21 times more likely than 2051-2080, unless carbon emissions are cut immediately. Such extreme heat waves are impossible without global warming.

The vulnerability of North America, Europe and China was staggering, said Eric Fischer, of ETH Zurich in Switzerland, who led the research. “Here we see the biggest jumps in the record-breaking events. This is really worrying,” he added.

“A lot of places haven’t yet seen anything close to what’s possible, even in current conditions, because just looking at past history is really dangerous.”

Soldiers check the damage after the flooding of the Ahr River, in Resch in the county of Arweiler, Germany, on July 21. Photo: Friedemann Vogel/EPA

The study also showed that record-breaking events can come in the form of sharp bursts, rather than becoming progressively more frequent. “This is really concerning,” Fisher said. “Planning for heat waves that increase in intensity by 0.1°C every two or three years is still very worrying, but it would be much easier to prepare for them.”

Professor Michael Mann, from Penn State University in the US and not part of the new research said: “This study underscores something that was clear in the extreme weather record we saw this summer: dangerous climate change here, and it is now simply a question of how severe we are willing to allow her to get it.” Mann’s same research published in May showed that heat stress in the United States could double by 2100.

But he said, “If anything, this latest study, and ours, underestimates the potential for deadly extreme temperatures in the future, in the absence of significant climate action” because current climate models do not capture the slow and very persistent nature of the extreme weather events that have been seen. In the Pacific Northwest heat wave and recent German floods.

The new research, published in the journal Nature Climate Change, concludes that “record-breaking extremes are [currently] Very rare but its expected probability will increase rapidly in the next three decades.”

It found that the rate of global warming was critical to the increased risk, not just the global temperature that was reached. This points to the need for sharp reductions in emissions as quickly as possible, rather than continuing emissions and being sucked back out of the atmosphere at a later time.

The scientists used a scenario in which carbon emissions are not reduced, which some experts have argued is unrealistic, given that some climate action is being taken. However, with the exception of the light wave caused by the coronavirus pandemic, global emissions have not yet come down, and the researchers argue that the scenario remains favourable until carbon dioxide emissions continue to decline.

The researchers said rare, record-breaking events in the past had massive impacts, such as the 2010 Russian heat wave, which killed 55,000 people and damaged $15 billion in crops, and the 2003 European heatwave, which led to 70,000 premature deaths.

“With temperature records smashing in North America and devastating floods in Europe and China just last month, it is clear that climate change is affecting the planet,” said Vicki Thompson, from the University of Bristol in the UK. “The need to understand what could happen in the future is vital to allow us to adapt.”

“The good news is that we can prevent the worst case seen in this study,” she said. The study showed that if emissions began to drop immediately and rapidly, the risk of record-breaking extremes would drop by about 80%. “As Cop26 approaches, we should hope that policy makers will use evidence like this to show the need for global emissions cuts,” Thompson said.

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