Hotter, longer and deadlier! Climate change makes UK's 40°C heatwaves 20 times more likely

A Met Office study warns that 40°C heatwaves are now 20 times more likely in the UK than in the 1960s. Southern England could reach 46.6°C, threatening health, infrastructure and the environment.

Record-breaking heat in UK no longer rare, says study

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A new study published in the journal Weather has revealed that extreme heat events in the UK, like the one in July 2022 that surpassed 40°C for the first time, are now over 20 times more likely than they were in the 1960s.

Scientists at the UK Met Office's Hadley Centre used advanced climate simulations to show how the country’s risk from extreme temperatures has increased sharply due to climate change.

One of the most alarming findings

Southern England could now experience summer temperatures as high as 46.6°C, approaching Europe’s all-time high of 48.8°C. According to the research team, there is a 50% chance that the UK will breach 40°C again within the next 12 years.

Longer and hotter heatwaves ahead

The team found that the long-term heatwaves lasting over a month above 28°C are now possible in parts of southeast England. Using detailed storylines and data from UNSEEN (UNprecedented Simulated Extremes using ENsembles), the researchers were able to simulate multiple future heatwave possibilities that have not yet been observed, offering valuable tools for stress-testing the country’s resilience.

Heat impacts already being felt

The 2022 UK heatwave was linked to more than 2,800 deaths. It also caused wildfires, melted roads, and buckled railway tracks, even in urban areas. Vulnerable populations suffered the most, raising concerns about how the UK can cope with future, even more intense events.

Western Europe, including the UK, is recognised as a global hotspot for rising heatwaves. Scientists say this is due to both global warming and changing atmospheric patterns. What makes the findings especially concerning is that most existing climate models have underestimated how fast temperatures are rising in the region.

The study also used non-stationary statistical models to account for both the increasing average temperatures and the wider range of extremes. This provides a more accurate estimate of just how severe and frequent UK heatwaves could become.

The research highlights that climate adaptation is no longer optional. With record temperatures becoming more common, the UK must invest in heat-resilient infrastructure, public health systems, and emergency response mechanisms to cope with the escalating threat of extreme summer heat.