The problem is not unique to the UK. Mainland Europe is experiencing its third major heatwave this year, with temperatures reaching 47C in parts of Spain. Many parts of Europe suffered an unusually dry spring, leading to widespread drought conditions and increasing the chance of wildfires during periods of extreme heat – as Portugal is now experiencing. The inescapable truth is that heat waves are happening more often and getting hotter, and this is due to human-caused climate change. Here in the UK, 40C summers are becoming more and more likely. Earlier this week, forecast models showed simulations exceeding that mark, suggesting that it is naturally possible in the current climate. We are unlikely to reach those temperatures this month, with most forecast models showing highs in the mid-30s, but scientists at the Met Office have shown that by the end of the century the UK could have 40 C days every three to four years high emissions scenario. If emissions are reduced to stay within the Paris climate agreement, the probability drops to about every 15 years. Right now we’re well on our way to somewhere in between. Last June, western North America experienced a record-breaking heatwave, with Canada setting a new national record temperature of 49.6C, nearly 5C higher than previously seen. An extreme of this magnitude was unthinkable before it happened, but a study last year showed that hot temperatures are expected in a world experiencing undeniable climate change. The project highlighted Europe as one of the regions most at risk from these record-breaking heatwaves. According to lead author Erich Fischer – as in disciplines like the high jump, where world records are old and broken only in small increments – the record-breaking heat should become rarer and the margins narrower the longer we count. But due to climate change we are seeing the opposite. the climate right now is behaving like an athlete on steroids. Another recent study identified Europe as a scorching heat wave, with the extremes rising three to four times faster than the rest of the mid-latitudes. Changes in the jet stream that cause more persistent heatwaves are contributing to this accelerating trend, the research showed. As temperatures become increasingly dangerous, rapid adaptation will be key to reducing the impact of heatwaves on society. There are several relatively simple measures that would help. The effects of heat are magnified in cities, and with nearly 70% of the world’s population expected to live in cities by 2050, it is essential to think about extreme temperatures in urban planning. Adding more green spaces to cities would help lower air temperatures and create shaded areas, reducing the need for mechanical cooling. Not only would this be beneficial in a heat wave, but it would also make cities nicer places to live. The benefits of adding green spaces are endless. They have been shown to reduce air pollution and flood risk and improve mental health and create better social cohesion. As we look toward the end of the century, there is reason for cautious optimism. Although heat waves are expected to become hotter and more frequent as emissions continue, the most extreme events can be avoided through mitigation. Any reduction in future emissions will help reduce the size of the heatwaves we face. The sooner the world can achieve net zero greenhouse gas emissions, the sooner these alarming trends will stabilize. Vikki Thompson is a climatologist at the University of Bristol
