Daily Junction.mobi portalNews · July 20, 2022 · Daily Junction Editorial Team · 12 min
July 2022 saw the UK record its hottest ever temperature of 40.3°C, causing runways to buckle, rails to warp, and over 2,800 excess deaths. The heatwave exposed Britain's vulnerability to extreme heat and forced a reckoning with climate adaptation.
On July 19, 2022, Britain crossed a threshold that many thought impossible: the temperature reached 40.3°C (104.5°F) at RAF Coningsby in Lincolnshire, shattering the previous UK record of 38.7°C set in 2019. For a country accustomed to mild summers and obsessed with complaining about drizzle, the heatwave was a profound shock. Runways melted, railway lines buckled, roads cracked, and hospitals were overwhelmed with heat-related emergencies. Over 2,800 people died in the space of a week—more than most terrorist attacks or natural disasters in modern British history.
The July 2022 heatwave was not just a weather event; it was a climate wake-up call. The Met Office issued its first-ever red extreme heat warning, indicating that even healthy people were at risk. Schools closed, businesses sent workers home, and the government activated emergency protocols usually reserved for major incidents. Climate scientists confirmed what many had feared: the heatwave was made at least 10 times more likely by human-caused climate change, and events like this would become increasingly common unless global emissions were slashed.
The heatwave began building in mid-July as a high-pressure system settled over the UK, drawing hot air from North Africa and southern Europe. By July 17, temperatures were already in the low 30s across much of England, but forecasters warned that the worst was yet to come. The Met Office issued an amber extreme heat warning on July 15, upgraded to red on July 18—the first time such a warning had ever been issued for heat in the UK.
July 19 was the peak. By mid-afternoon, temperatures had exceeded 40°C at multiple locations. RAF Coningsby in Lincolnshire recorded 40.3°C at 3:12 PM, making it the hottest place ever measured in the UK. Other stations reported similarly extreme temperatures: 40.2°C at Heathrow, 39.1°C at Kew Gardens in London, and 38.1°C at Cambridge. Even Scotland, typically much cooler, saw temperatures reach 34.8°C at Charterhall in the Borders.
The overnight temperatures were almost as remarkable. On the night of July 18-19, temperatures in central London did not drop below 25°C—a tropical night by meteorological definition. This was significant because the human body needs cooler nighttime temperatures to recover from daytime heat stress. When nights remain hot, the health risks compound, particularly for the elderly and those without access to cooling.
The heatwave was not just about peak temperatures. It was the sustained nature of the heat that made it so dangerous. From July 17-20, large parts of England experienced four consecutive days above 35°C, with minimal relief at night. This prolonged exposure overwhelmed the body's ability to regulate temperature, leading to heat exhaustion and heatstroke even among people who took precautions.
The UK's infrastructure was simply not designed for 40°C heat, and the failures were spectacular. At London Luton Airport, the runway surface melted, forcing the airport to suspend flights for several hours while emergency repairs were carried out. RAF Brize Norton, the largest RAF base, also suspended flights due to runway damage. Images of bubbling tarmac and cracked concrete circulated on social media, illustrating the physical reality of climate change.
The railway network suffered catastrophic failures. Network Rail imposed blanket speed restrictions across much of the country, with trains limited to 20 mph on some sections to prevent rails from buckling. Steel rails expand in heat, and if they expand too much, they can warp or "sun kink," derailing trains. Despite the precautions, several lines were closed entirely when rails buckled. The East Coast Main Line, one of the UK's busiest routes, saw severe disruptions for days.
The restrictions caused chaos for passengers. Trains were cancelled or delayed by hours, and those that did run were often overcrowded and lacked air conditioning. Videos of passengers fainting on sweltering trains went viral, prompting anger at the rail industry's lack of preparedness. Network Rail defended the speed restrictions as essential for safety, but critics pointed out that countries like Spain and Italy operate trains at high speed in 40°C+ heat, suggesting that UK infrastructure was simply not fit for purpose in a warming climate.
Roads also suffered. The A1(M) in Yorkshire and the M25 near London both experienced surface failures, with tarmac cracking and melting. Highways England deployed emergency crews to repair damaged sections, but the sheer scale of the problem overwhelmed resources. Drivers were warned to avoid non-essential travel, and breakdown services reported record call-outs for overheating vehicles.
Hospitals and healthcare facilities faced their own challenges. Many older hospital buildings lacked adequate cooling, with ward temperatures exceeding 30°C. Staff used fans and ice packs to keep patients cool, but the conditions were far from ideal. The NHS declared a Level 4 heat-health alert—the highest level—and cancelled non-urgent procedures to free up capacity for heat-related emergencies.
Power networks came under strain as demand for cooling surged. While the UK did not experience blackouts, National Grid warned that the margin between supply and demand was tight. Air conditioning units, fans, and refrigerators all drew extra power, and the heat reduced the efficiency of power stations and transmission lines. In a preview of future challenges, solar panels actually became less efficient in the extreme heat, as high temperatures reduce the electrical output of photovoltaic cells.
The most tragic consequence of the heatwave was the loss of life. The UK Health Security Agency (UKHSA) estimated that 2,803 excess deaths occurred during the heatwave period (July 17-25, 2022). Excess deaths are calculated by comparing the actual number of deaths to the expected number based on historical averages, accounting for seasonal variations.
The majority of victims were elderly, with over 80% of excess deaths occurring in people aged 65 and above. Pre-existing health conditions—particularly cardiovascular and respiratory diseases—were significant risk factors. Heat stress places enormous strain on the heart and lungs, and for people with weakened systems, this can be fatal. Dehydration, electrolyte imbalances, and heat stroke were direct causes of death, while heart attacks and strokes triggered by heat stress were indirect causes.
Vulnerable populations were disproportionately affected. People living alone, those in poorly ventilated housing, and individuals with limited mobility or cognitive impairment were at highest risk. Homeless people faced extreme danger, with several deaths reported among rough sleepers who had no access to shade or cooling. Outdoor workers—construction laborers, delivery drivers, agricultural workers—also faced significant risks, though most employers implemented heat safety measures like frequent breaks and hydration.
The UKHSA's analysis revealed stark geographic and socioeconomic disparities. Excess deaths were concentrated in urban areas, particularly London and the Midlands, where the urban heat island effect amplified temperatures. Deprived communities experienced higher death rates than affluent areas, reflecting differences in housing quality, access to healthcare, and awareness of heat risks.
Mental health impacts were also significant, though harder to quantify. Heat is known to exacerbate mental health conditions and increase aggression and irritability. Emergency services reported a spike in mental health crises during the heatwave, and domestic violence incidents increased. The psychological stress of extreme heat—sleepless nights, fear for vulnerable family members, anxiety about climate change—took a toll that extended beyond the immediate physical dangers.
In the immediate aftermath of the heatwave, the World Weather Attribution (WWA) initiative—an international collaboration of climate scientists—conducted a rapid attribution study to determine the role of climate change. Their findings were unequivocal: the heatwave was made at least 10 times more likely by human-caused climate change, and the peak temperatures were approximately 2°C higher than they would have been in a pre-industrial climate.
The study used climate models to compare the likelihood of such a heatwave in the current climate (with about 1.2°C of global warming) versus a hypothetical world without human influence. The results showed that in a pre-industrial climate, a 40°C day in the UK would be virtually impossible—a once-in-several-thousand-years event. In the current climate, it is a rare but plausible occurrence, with a return period of roughly 100-300 years. If global warming reaches 2°C above pre-industrial levels, such events could occur every 15-20 years.
The physical mechanism is straightforward. Greenhouse gas emissions trap heat in the atmosphere, raising average temperatures. This shifts the entire distribution of temperatures upward, making extreme heat events more frequent and intense. Additionally, climate change is altering atmospheric circulation patterns, making high-pressure systems—which bring settled, hot weather—more persistent over Europe.
The Met Office's UK Climate Projections (UKCP18) paint a sobering picture of the future. Under a high-emissions scenario (RCP8.5), summer temperatures in the UK could rise by 5-6°C by 2100, making 40°C+ days routine. Even under a moderate-emissions scenario (RCP4.5), summer temperatures are projected to rise by 2-3°C, meaning that the exceptional heatwave of 2022 would become a typical summer event by mid-century.
Beyond the immediate human and infrastructure toll, the heatwave had wide-ranging economic and social impacts. Businesses lost productivity as workers struggled in the heat or were sent home. The Trades Union Congress (TUC) called for a maximum workplace temperature law, arguing that current regulations—which set a minimum temperature but no maximum—are inadequate for a warming climate.
Agriculture suffered significant losses. Crops wilted in the heat, and livestock experienced heat stress, reducing milk yields and weight gain. The National Farmers' Union estimated losses in the tens of millions of pounds, with some farmers forced to cull animals due to lack of water. Water companies imposed hosepipe bans across much of southern and eastern England as reservoirs and rivers dropped to critically low levels.
The heatwave also exposed inequalities in housing. Modern, well-insulated homes designed to retain heat in winter became unbearable in summer, with indoor temperatures exceeding outdoor temperatures. Flats in high-rise buildings, particularly top floors, were especially affected. Residents reported indoor temperatures of 35°C+ at night, making sleep impossible. In contrast, wealthier households with air conditioning or the ability to escape to cooler locations were largely insulated from the worst effects.
Education was disrupted as schools closed or sent pupils home. Exam boards faced criticism for requiring students to sit exams in sweltering conditions, with reports of students fainting in exam halls. The incident prompted calls for climate-proofing schools with better ventilation, shading, and cooling systems.
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