40C in the UK. How soon could it happen again?

BBC News

2 days ago

On 19 July 2022, the UK experienced its first recorded temperature above 40C, when Coningsby in Lincolnshire reached 40.3C.Three years on, climate change continues to have an impact. According to the Met Office: "Temperatures several degrees higher than we saw in the summer of 2022 are possible in today's climate."The Met Office also estimates there is a 50-50 chance of seeing a 40C day again, and sooner than you may think.
Records tumbled three years ago
The record heat in summer 2022 was well forecast. I remember computer models signalled 40C many days ahead. There was a gasp around the BBC Weather Centre when we saw that. We thought temperatures could reach 40C at some time in the next 25 years, but certainly not so soon.It is not just that the record was broken…it was smashed! Normally, temperature records are broken by a few tenths of a degree. The measurement was a full 1.6C higher than the previous maximum temperature of 38.7C set at Cambridge Botanical Gardens in summer 2019.The record heat was recorded over a large area too. A remarkable 46 weather stations met or exceeded the previous record. Bramham in Yorkshire reached 39.8C, breaking the previous record temperature by a staggering 6.3C.At the time, Dr Mark McCarthy, from the Met Office, stated: "In a climate unaffected by human-induced climate change, it would be virtually impossible for temperatures in the UK to reach 40C."
Where did this hot weather come from?
The record heat in 2022 coincided with high temperatures in Europe. A long running drought and a number of extreme heatwaves made summer 2022 the hottest on record on the continent, according to Copernicus Climate Change Service, external. This led to an unusually high number of wildfires, especially in France and Spain. Over the past 30 years, temperatures in European countries have increased by more than twice the global average.The temperature in Portugal reached 47C in July 2022, the hottest ever for that month. It was the longevity of the heat in south-western Europe that was particularly unusual, and this tends to be where our hot weather comes from. Southerly winds, originating from southern Europe or north Africa, bring heat and high humidity our way, just as in July 2022.
How soon will this happen again?
Worryingly, it could happen sooner than you would expect. A recent study by the Met Office revealed that the chance of the temperatures exceeding 40C is increasing., externalDr Gillian Kay, Senior Scientist at the Met Office, stated that the chance of 40C "is now over 20 times more likely than it was in the 1960s." She continued, "we estimate a 50-50 chance of seeing a 40C day again in the next 12 years."Climate change is leading to heatwaves lasting longer, happening more often and being more severe. And we have already had three of them this year.
What about the rest of our summer?
Our highest temperatures of the summer tend to come in July or August as the air and land heats up more.However, this year an Atlantic influence looks more likely later in July and August. This would mean west or south-westerly winds which would keep temperatures a bit lower. There will be spells of high pressure and bursts of hot air though. One computer model predicts a longer period of hot weather later in August, but this is a less likely scenario.The highest temperature so far this year is 35.8C recorded on 1 July in Kent. It is possible the temperature could get close to this again in south-east England but unlikely.You can see how hot it will get where you are on the BBC Weather app.