Recent research published in the Weather journal by Met Office scientists, highlights the rapidly growing likelihood of extreme heat in the UK. The findings show a clear trend: the chance of extreme heat has been increasing with climate change. The research suggests that the UK should prepare for longer and hotter heatwaves than the country has previously experienced, emphasising the vital importance of investing in adaptation now.

In 2022, the UK experienced its first recorded temperature exceeding 40°C during Europe’s hottest summer on record. The new study suggests that the chance of temperatures reaching over 40°C is accelerating. Using simulations from a decadal prediction model, researchers generated a large set of plausible climate outcomes in the current climate, enabling assessment of the frequency and intensity of extreme temperatures today, as well as analysing how they have changed over recent decades.

Lead author, Met Office scientist Dr Gillian Kay explained the striking increase in risk: the chance of UK temperatures exceeding 40°C is now over 20 times more likely than it was in the 1960s. As the climate continues to warm, this risk will grow. “We estimate a 50-50 chance of seeing a 40°C day again in the next 12 years,” said Dr Kay.

Information on present and future heatwave risk is vital for organizations involved in disaster response. The ASPECT project is working to translate this kind of scientific insight into practical action for our key partner organizations (our ‘Super Users’). Dr Freya Garry explains:

“In the ASPECT project we are working with the British Red Cross to help them better understand present and future heatwave risk in the UK. In developing climate services under ASPECT, we are using a toolbox of different types of seamless climate information. This work by the Met Office is a really useful addition, revealing that the likelihood of extreme heat events in the UK has been rapidly increasing.”

One of the most concerning findings of the study is that the chance of 40°C is rising rapidly. This elevates the threat not only to health but also to infrastructure and public services, making adaptation strategies essential. Dr Garry adds:

“Importantly, the new research shows that the UK is at risk of more hot days than we have actually observed. This is critical for risk assessment for organisations like British Red Cross. As responders tackle the challenges of prolonged heat in the summer, the British Red Cross is using climate information to help with their decision making. For example, do they have enough responders in the right places, with the right equipment, to help the most vulnerable members of society?”

The study also sheds light on the potential for extended heatwaves, finding that in today’s climate, heatwave conditions could persist for a month or more in Southeast England. “The new research also reveals storylines of long duration hot periods that the method demonstrates may be possible in the South-East of England,” says Dr Garry. “These would be events with potentially severe health impacts that we could prepare for now.”

With climate extremes becoming more likely, studies like this are vital for informing how we adapt. The full paper by Kay et al. is available online in the Weather journal.

The implications of heatwaves are particularly pertinent in the light of new research released last week revealing the increasing risk that rising temperatures pose to human health in the coming decades. This new study by researchers at UCL and the London School of Hygiene and Tropical Medicine found that even if temperature increase is limited to 1.6°C of warming above preindustrial levels and high levels of adaptation are put in place, heat-related deaths are projected to increase up to sixfold by the 2070s in England and Wales. The health impacts of climate change will be significant to society, even in a cooler European country such as the UK, emphasising the importance of adaptation and preparation for climate impacts now.