Searing heat this week made ‘100 times more likely’ by climate change, say scientists

A rapid study by the World Weather Attribution (WWA) research group also found the current heatwave in the south-east of England was around 10 times more likely than without human activity warming the planet.

Dr Fredi Otto, from Imperial College London, warned heatwaves are “silent killers”, with the impacts of heat “severely underestimated” and the UK unprepared for the kind of conditions hitting the country into the weekend.

Older people are at the highest risk of death, as well as those with heart issues, respiratory illnesses and conditions such as diabetes, while this kind of heatwave earlier in the summer is more deadly as people are less acclimatised to coping with the warmer conditions, the experts warned.

And wildfires are an “emerging risk” in the summer in the UK, with conditions becoming more like southern Europe, the researchers said as they urged people to be very careful about barbecues, cigarettes and glass which can all ignite fires in the hot, dry weather.

The study by WWA, which seeks to provide rapid assessments of the role of climate change in specific extreme weather events such as heatwaves or rainstorms that lead to flooding, is only the second time it has analysed an event as forecasted rather than one that has just happened.

The analysis, which drew on observations for early summer heat in the south east of the UK, found that a heatwave – defined as three days of temperatures above 28C for the region – in June would be expected once every five years today.

But without humans warming the atmosphere by around 1.3C since pre-industrial times, such a heatwave would only have occurred about once every 50 years, the study shows.

The heatwave was made approximately 2-4C more intense as a result of the overall warming of the planet, meaning the current weather “just wouldn’t have been a heatwave without human-induced warming”, Dr Ben Clarke, from Imperial College London, said.

Temperatures had been forecast to hit 32C across the south east on Saturday and had already reached that level on Thursday in London.

Heat of that level could be expected in June once in 25 years in the current climate, but only once in 2,500 years in June before industrialisation, the researchers said.

While the impacts of temperatures rising above 30C are not as severe as the record-breaking heat topping 40C in some places in July 2022, the researchers warned people were still at risk.

They urged people to ensure they were drinking enough water, and to encourage elderly relatives to do the same, avoid areas with high air pollution, keep windows and curtains shut during the day, and consider going to cooler public buildings such as museums to protect against the heat.

Dr Clarke, researcher at the Centre for Environmental Policy at Imperial College London, said: “This heatwave is another reminder that our planet has already heated to a dangerous level.

“We’re at 1.3C today, but heading for around 3C this century.

“With every fraction of a degree of warming, the UK will experience hotter, more dangerous heatwaves.

“That means more heat deaths, more pressure on the NHS, more transport disruptions, tougher work conditions and poorer air quality.”

Dr Otto, associate professor in climate science at the Centre for Environmental Policy, said: “We know exactly what has intensified this heatwave – burning oil, gas and coal, which has loaded the atmosphere with planet-heating greenhouse gases.

“It is totally insane we have political leaders in the UK trying to drag us back to the past with calls for more fossil fuels.

“The climate will continue to drive increasingly dangerous heatwaves, fires and floods in the UK until emissions are reduced to net zero globally.”

She added that while people working in air conditioned offices would “probably be OK” this week, poorer people working outdoors, in kitchens or other hot environments and then returning home to poorly insulated flats would be enduring hot conditions throughout.

“Making our societies more equal is essential to reduce the impacts of climate change,” Dr Otto said.

It comes as the UK could break its record for the warmest day of the year for the second day in a row, with temperatures up to 33C forecast.

Temperatures reached as high as 32.2C in Kew, west London, on Thursday, amid an amber heat-health alert for all regions in England.

It means the UK could break the record for the hottest day of the year just one day after it was broken on Thursday, as temperatures of 33C are forecast.

The previous hottest day of the year was last Friday, when the mercury hit 29.4C in Santon Downham, Suffolk.

The amber alert, issued by the UK Health Security Agency (UKHSA) for the first time since September 2023, is in force until 9am on Monday.

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It warns "significant impacts are likely" across health and social care services because of high temperatures, including a rise in deaths, particularly among those aged 65 and over or people with health conditions.

Meanwhile, temperatures are forecast to reach the low 30s and could potentially hit 33C on Friday, the Met Office said.

And by Friday afternoon a number of areas are expected to have passed the heatwave criteria, Met Office weather forecaster Dan Stroud said.

An official heatwave is recorded when areas reach a certain temperature for three consecutive days, with thresholds varying from 25C to 28C in different parts of the UK.

Mr Stroud said: "We're expecting the hot and dry conditions to continue, it does turn a little bit hazier in the west during the course of Friday, we're still expecting temperatures to reach the low 30s, 31C, 32C fairly widely, maybe seeing 33C."

Increasing amounts of cloud will move in from the west on Saturday, with a chance of showers, some which could be thundery in North Wales and north-west England, while eastern areas will see another dry and hot day, he added.

Temperatures will be in the low 30s, and probably be the peak of the hot spell on Saturday, as 34C is possible, still below the June record of 35.6C in 1976.

Sunday will be another very warm day in the south and east probably in the late 20s, elsewhere it will be cooler, with temperatures in the mid 20s, Mr Stroud said.

It comes after a warning has been issued as firefighters have responded to more than 500 wildfires across England and Wales this year so far.

As of Thursday, 564 wildfire incidents have been responded to by English and Welsh fire and rescue services so far this year, which is a 717% increase on the same period in 2024, and more than double the number seen in 2022 which went on to be the worst year on record for wildfires, the National Fire Chiefs Council (NFCC) said.

The NFCC is now urging caution among members of the public when enjoying the outdoors in a bid to prevent further spikes in incidents.