UK heatwave: Met Office declares health emergency with 50 per cent chance of 40°C heat

By Adam Vaughan

The UK Met Office has declared an emergency over the heatwave that is forecast to hit at the start of next week, with hospitals bracing for a spike in admissions when temperatures peak on Monday and Tuesday.

The level 4 alert issued today is the highest level possible and includes a warning that central and eastern England will be the hottest areas, with “population-wide adverse health effects experienced” plus “widespread impacts on people and infrastructure”.

The weather agency says there is now a 50 per cent chance of the temperature hitting the totemic milestone of 40°C for the first time, and an 80 per cent chance of it breaching the 38.7°C record set in 2019, as hot air moves north from France and Spain. Meteorologists have warned that Europe is facing potentially its worst heatwave in more than two centuries.

“It is striking for me, because of the temperatures we might see on Monday and Tuesday,” says Peter Stott at the Met Office. “We might break the 2019 record, which in itself was a pretty extraordinary temperature. We’ve definitely got the conditions that could give us 40°C.  These are the sort of temperatures that our analysis shows we just wouldn’t be getting without climate change.”

Without human-caused climate change, the chance of 40°C temperatures in the UK would be vanishingly small, an event with the potential to occur once every 1000 years. But research by Stott shows that the greenhouse gases pumped into the atmosphere by factories, cars and other activities have increased that risk to around 1 in 100 years — and it could happen every 3.5 years by 2100 in a high-emissions scenario. Scientists say all heatwaves today can now be considered to have been made more likely by climate change.

Whether or not the temperature reaches 40°C next week, the intense heatwave is expected to affect large swathes of the UK economy and society. “I am hugely concerned by the extreme heat warning,” says Chloe Brimicombe at the University of Reading. “We will already have experienced heat-related deaths and we are simply not prepared for this prolonged intense heat.”

In the short term, she says community cooling rooms should be opened, similar to those in London’s “cool spaces” network. A report this week by the University of Manchester, UK, found that, after factoring in social deprivation, Birmingham topped a list of UK’s most vulnerable neighbourhoods to extreme heat.

According to the UK Health Security Agency (UKHSA), about 1600 people died in the UK because of heatwaves in 2021 and about 2500 in 2020. The number of heat-related deaths in the UK is expected to rise to up to 7000 a year by 2050 without sufficient adaptation. UK hospitals have already seen rising admissions in recent weeks due to another covid-19 wave, while the NHS 111 medical helpline has been experiencing an increase in calls this month about heat exposure.

The Met Office says that high night-time temperatures next Monday are a concern in some parts of the country, especially London, meaning people will have little relief. The UK’s minimum temperature record, of 23.9°C at Brighton in 1990, is expected to be beaten, with a high probability of 25°C in London and several areas further north.

Several people told New Scientist that their children’s school is closing or closing early on Monday due to the heatwave. However, the UKHSA says it doesn’t believe there is any public health reason for school closures.

A UK Department for Education spokesperson says: “There is clear government guidance available online to help school staff look after children in the hot weather, including the use of ventilation, keeping children hydrated and avoiding vigorous physical activity for pupils. Individual school leaders are responsible for managing their own local circumstances, but we are not advising schools to close.”

Richard Millar at the independent Climate Change Committee in the UK says there will be impacts on infrastructure, from energy to transport. He says rails buckling at high temperatures are likely to lead to speed restrictions and train delays. Coal and gas-fired power stations are less efficient at high temperatures, and networks including pylons experience greater energy losses too. National Grid ESO, the electricity system operator for Great Britain, says it is monitoring the situation, but isn’t expecting extraordinary energy demand next week as people try to keep cool.

However, Millar says there may be greater energy demand for cooling in future heatwaves, as climate change raises global average temperatures beyond the 1.1°C of warming to date. While very few UK homes have air conditioning today, he says a key unknown is how many will install it in the future, increasing electricity demand and financial costs. A 2021 study for the UK government estimated that homes, primarily in England, could account for at least 75 per cent of the country’s cooling energy needs by the end of the century. Millar says it would be better if people adopted passive measures at home, such as external shades, white roofs and closing blinds and curtains on sun-facing sides of buildings.

The current heatwave is affecting the natural world too. The Wildlife Trusts, a network of charities across the UK, says grazing animals are being forced to seek shade for longer periods. Water levels are very low in some areas, including the Brockadale nature reserve in Yorkshire. Trusts in Sheffield, Staffordshire and Cornwall have been preparing by creating fire breaks and digging fire ponds to reduce the risk of wildfires.

“Wildlife has had to cope with changing climatic conditions before, but, historically, that has happened over centuries,” says Kathryn Brown at the Wildlife Trusts. “Species are now being faced with extreme changes over much shorter spaces of time.”

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