It's always hard to tie individual events to large-scale trends like climate change. But the heatwaves that affected North America, Europe, and China in July would have been extremely unlikely without man-made climate change. As the authors of a new study show, our emissions are fueling such extreme events -- and we're woefully unprepared for this level of heat.
The World Weather Attribution, a group of international scientists, spent a week looking into the heatwaves that affected large parts of the Northern Hemisphere in July. To understand the influence of climate change, they examined weather data and computer models to compare the current climate with the climate of the past.
Without climate change, the heatwaves would have been extremely rare, the researchers said. In China, it would have been about one in a 250-year event, while in the US and Europe, it would have been “virtually impossible” to happen. Events like this could now happen every 10 years in the US, every five in China and every 15 in the US.
“The result of this attribution study is not surprising. The world hasn’t stopped burning fossil fuels, the climate continues to warm and heatwaves continue to become more extreme. It is that simple,” Friederike Otto, study author, said in a statement. “We still have time to secure a safe and healthy future but we need to stop burning fossil fuels.”
Local records were broken in Italy and Spain in July, as temperatures edged toward Europe’s all-time record of 48.8 degrees Celsius. Meanwhile, temperatures in Death Valley reached 53.5 °C, with Phoenix experiencing 25 straight days of temperatures over 43.3°C. China also saw an all-time record of 52.2°C.
The study wasn’t published in a peer-reviewed scientific journal yet but follows scientifically accepted techniques. The researchers regularly follow extreme weather events around the world, such as heatwaves and droughts, and then publish reports on the climate connection, as they recently did with floods in Rwanda and in Italy.
Heat in Southern Europe 👇 & North America impossible without human-induced climate change - new @WWAttribution study. Totally unsurprising but important result. This is what climate change looks & feels. We need to adapt, we need to stop making it worse. https://t.co/3soEuDF7CP pic.twitter.com/3wmXmd8JqW
— Dr Friederike Otto (@FrediOtto) July 25, 2023
Countries have committed in the 2015 Paris Agreement to limiting warming to 1.5°C above pre-industrial levels. However, the world has already warmed 1.1°C, and current climate pledges are not ambitious enough to meet the 1.5°C target -- not even close.
In fact, our current emissions trajectory puts us on a path for way more frequent and intense extreme weather events, such as the heatwaves.
In their study, the researchers found that climate change has not only increased the likelihood of the recent heatwaves in the Northern Hemisphere but has also made them hotter. The heatwave in Europe was 2.5°C hotter because of climate change, while in North America it was 2°C hotter and in China, it was 1°C hotter, according to the study.
And we could be facing an even worse scenario. “These events will become even more common and the world will experience heatwaves that are even hotter and longer-lasting,” the researchers wrote. In fact, they estimated that a heatwave like the recent ones would happen every two to five years in a world that fails to meet the Paris targets.
The report is accessible here.