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Last Friday, the UK experienced its hottest day in August for 17 years as temperatures hit an unbearable high of 36.4 Celsius in the south east of England. That came just two weeks after the Met Office logged the UK’s third hottest day on record, when temperatures soared to 37.8C.
For many, it feels like this never-ending series of summer heatwaves is becoming more intense every year. And while thousands of people might have flocked to the beach to bathe in the scorching sun, many are also left wondering – is this the new normal? And has the climate crisis made sweltering heatwaves like this one more likely to occur?
For many climate scientists, the answer is a resounding yes. The World Weather Attribution initiative (WWA) has been conducting analyses of recent extreme weather events to try and understand if the climate crisis has exacerbated these phenomena by comparing extreme weather events with models in which carbon emissions have not altered the temperature of the Earth.
In July 2019, the UK experienced its highest temperature on record when it reached 38.7C in Cambridge. In a report released shortly after the summer 2019 heatwave swept Europe, the WWA found that the heatwave in the UK was made twice as likely because of climate change. While in the Netherlands and France, where temperatures reached 40.7C and 41.2C respectively, the climate crisis had made the record-breaking heatwave 100 times more likely.
“If the whole world warms, the UK warms. If the summer warms, heatwaves warm,” says Geert Jan van Oldenborgh, a climate researcher at the Royal Netherlands Meteorological Institute, which is a part of the WWA. The most notable aspect of the current heatwave that we’re all suffering through, says van Oldenborgh, is the sheer length of it, which is reflected in the high weekly average temperatures. “This shows up even more in the night-time temperatures,” he says. “Here in the Netherlands, the weekly mean minimum temperatures this week are more than two degrees above the previous record.”
Since before the beginning of the industrial revolution, the global temperature has risen by around 1C, making the chance of heatwaves like the one we’re experiencing right now consistently likelier. And, when they do occur, they’re also more likely to be hotter and longer. The WWA found that the highest daily average temperature each year was noticeably warmer across the globe than it was a century ago, with the only exceptions being the Eastern United States and India – where other factors had already increased the intensity of those heatwaves.
The intensity of other extreme weather events have already been linked to the climate crisis. The Australian bushfires which started in late 2019 are estimated to have been made more likely to occur by at least 30 per cent because of the climate crisis. WWA researchers even warned that a 30 per cent increase could be a conservative estimate because the climate models tend to underestimate the increases in extreme temperatures. “Those conditions wouldn’t have been so hot if it hadn’t been for climate change,” says Ed Hawkins, professor of climate science at the University of Reading, who was not part of the study. “These extra bumps in temperature potentially make the impacts worse, such as making it more likely to get bushfires.”
The study followed research from the Met Office, which found that the 2018 heatwave in the UK had been made 30 times more likely to occur than it would have been in the year 1750 because of the climate crisis increasing the concentration of carbon dioxide in the atmosphere
Intense thunderstorms, one of which is expected to strike the UK after the current heatwave subsides, are also likely amplified by the climate crisis. Warmer atmospheres absorb more moisture, which creates the perfect condition for severe storms to form, allowing potentially dangerous quantities of rain to fall in just a few days or even hours.
Linking extreme weather events to the climate crisis is important. Not only does it help us more easily see trends and patterns in the climate, but also to make better plans for a hotter future. “We’re going to get more days where we get certain hot temperatures, which cause problems to our infrastructure, such as roads or railways, or electronic networks, which struggle in the heat,” says Hawkins. “When we get these events, they’re very useful for talking about how we get used to them and learn how to deal with them better.”
Heatwaves haven’t just been getting more severe they’ve also been getting longer. And they’re only going to get worse as the years go by. The majority of the world has experienced heatwaves increase by a day every single decade since 1950, with heatwaves in lower-latitude areas increasing by between three and five days each decade. A further 13.8 per cent of the world’s population are estimated to suffer through heatwaves at least once every five years even if the globe warms by just 1.5C.
So what happens next? We have some difficult choices to make. “If we continue to emit greenhouse gases at the same rate as we are, then global temperatures will continue to rise, and these conditions will just get worse and worse,” warns Hawkins. “What happens next is completely down to us.”