When July’s heatwave swept through the Canadian province of Quebec, killing more than 90 people in little over a week, the unrelenting sunshine threw the disparities between rich and poor into sharp relief. While the well-heeled residents of Montreal hunkered down in blissfully air-conditioned offices and houses, the city’s homeless – not usually welcome in public areas such as shopping malls and restaurants – struggled to escape the heat. Benedict Labre House, a day centre for homeless people, was not able to secure a donated air-conditioning unit until five days into the heatwave. “You can imagine when you have 40 or 50 people in an enclosed space and it’s so hot, it’s very hard to deal with,” says Francine Nadler, clinical coordinator at the facility. Fifty-four Montreal residents were killed by this summer’s heat. Authorities have not so far specified whether any homeless people were among them, but according to the regional department of public health, the majority were aged over 50, lived alone and had underlying physical or mental health problems. None had air conditioning. Montreal coroner Jean Brochu told reporters that many of the bodies examined by his team “were in an advanced state of decay, having sometimes spent up to two days in the heat before being found”. Dying in a heatwave is like being slowly cooked. It’s pure torture … this heat can kill soldiers, athletes, everyone Professor Camilo Mora It was the poor and isolated who quietly suffered the most in the heat – a situation echoed in overheated cities across the world. In the United States, immigrant workers are three times more likely to die from heat exposure than American citizens. In India, where 24 cities are expected to reach average summertime highs of at least 35 degrees Celsius by 2050, it is the slum dwellers who are most vulnerable. And as the global risk of prolonged exposure to deadly heat steadily rises, so do the associated risks of human catastrophe. Last year, Hawaiian researchers projected that the share of the world’s population exposed to deadly heat for at least 20 days a year will increase from 30 per cent now to 74 per cent by 2100 if greenhouse gas emissions are allowed to grow. (It will rise to 48 per cent with “drastic reductions”.) They concluded that “an increasing threat to human life from excess heat now seems almost inevitable”. “Dying in a heatwave is like being slowly cooked,” said lead author Professor Camilo Mora at the time of publication. “It’s pure torture. The young and elderly are at particular risk, but we found that this heat can kill soldiers, athletes, everyone.” On the other side of the planet from Montreal, in Hong Kong, this newspaper reported as early as May that a heatwave had “reduced some of the city’s poorest residents to tears and left others fighting off bouts of depression” . With outdoor temperatures regularly topping 32 degrees, residents of Hong Kong’s notoriously cramped subdivided flats were found to be experiencing temperatures 10 degrees hotter at home. The Society for Community Organisation (SoCO), a non-governmental rights advocacy group, released the findings of a survey of 234 tenants. Almost half said they struggled emotionally in the heat, while a further 21 per cent claimed to have suffered from some form of depression. Lin Xiaohong wept when describing the living conditions in her 250 sq ft home on a rooftop in Tai Kok Tsui. “My 6½-year-old daughter only wears underwear at home as it is too hot. She can’t sleep and often has fever,” Lin told the South China Morning Post . “She has to shower three times at night. We have dinner at the park after making food at home.” Lin’s husband, a street cleaner and the family’s sole breadwinner, was earning HK$8,200 (US$1,040) a month. Some 55 per cent of his income went on rent, and the landlord charged the family HK$500 for electricity every month, rising to as much as HK$800 in summer. To save money, the Lins avoided using air conditioning, meaning the temperature at home regularly hit 37 degrees. For others in the city, the problem was even worse: SoCO measured the temperature at 27 subdivided units in June and July, and found that places in Yuen Long hit up to 42 degrees. The group urged the government to resume offering a living subsidy to “have-nots”, and build more transitional housing. (The wait for public housing in Hong Kong is at its longest in almost two decades, with families waiting for more than five years to be allocated a flat, according to official statistics released in May.) Killer temperatures Globally, 2018 is set to be among the hottest year since records began, with unprecedented peak temperatures engulfing the planet, from 43 degrees in Baku, Azerbaijan, to the low 30s across Scandinavia. In Kyoto, Japan, the mercury did not dip below 38 degrees for a week. In the US, an unusually early and humid July heatwave saw 48.8 degrees in Chino, inland of Los Angeles. Residents blasted their air conditioners so much they caused power shortages. Urban areas are reaching these killer temperatures faster than those that are less populated. Cities absorb, create and radiate heat. Asphalt, brick, concrete and dark roofs act like sponges for heat during the day and emit warmth at night. Air conditioning is a lifesaver for those who can afford it, but it makes the streets even hotter for those who cannot. How many more will have to die as Asia gets hotter “Urban heat islands, combined with an ageing population and increased urbanisation, are projected to increase the vulnerability of urban populations, especially the poor, to heat-related health impacts in the future,” a US government assessment warned. The World Health Organisation says that 60 per cent of people will live in cities by 2030, and the more densely populated they become, the hotter they will get. Considering that recent predictions warn temperatures in South Asia will exceed the limits of human survival by the end of the century, every degree counts. Even this year, 65 people have perished from nearly 44-degrees heat in Karachi, Pakistan – a city used to extreme heat. These problems are worse for vulnerable or low-income populations living near traffic in poor housing with no air conditioning Tarik Benmarhnia, public health researcher But the impact is not evenly distributed. For example, there is a strong correlation between an area’s green spaces and its wealth; when shade from tree canopies can lower surfaces’ peak temperature by 11 to 25 degrees, “landscape is a predictor for morbidity in heatwaves”, says Tarik Benmarhnia, public health researcher at University of California, San Diego. A review paper he recently co-authored found that people living in less vegetated areas had a 5 per cent higher risk of death from heat-related causes. In 2017, researchers at University of California, Berkeley were able to map racial divides in the US by proximity to trees. Black people were 52 per cent more likely than white people to live in areas of unnatural “heat risk-related land cover”, while Asians were 32 per cent more likely and Hispanics 21 per cent. Air pollution is more deadly in these areas, too, as nitrous oxides generate ozone when heated by the sun, inflaming airways and increasing mortality risk. “These problems are worse,” says Benmarhnia, “for vulnerable or low-income populations living near traffic in poor housing with no air conditioning.” But air conditioning will remain out of reach for many, even as it increasingly becomes a necessity. In 2014, Public Health England raised concerns that “the distribution of cooling systems may reflect socioeconomic inequalities unless they are heavily subsidised”, adding that rising fuel costs could further exacerbate this. And when we need to use less energy and cool the planet, not just our homes and offices, relying upon air conditioning is not a viable long-term plan – and certainly not for everyone. Earlier this month in China, Agence France-Presse reported that in sweltering Shanghai, with daily highs frequently topping 35 degrees, less affluent residents were escaping the heat of their cramped nearby homes by sleeping outside on benches or even directly on the pavement. Many homes in the city of 24 million people lack air conditioning, and overheated residents flocked to subway stations, shopping malls, libraries and supermarkets to escape. Air-conditioned outlets of Swedish furniture retailer Ikea – with beds and sofas on which to nap – were proving especially popular. ‘In Cairo everything is suffocating’ Most of the research into heatwaves and public health has focused on Western countries; Benmarhnia says more studies have been done on the city of Phoenix, Arizona, than the entire continent of Africa. But the problem is global, and especially pronounced across urban slums such as the ashwiyyat in Cairo, where temperatures during the city’s five-month-long summers have peaked at 46 degrees. Traditionally, Egyptians built low buildings close together, forming dense networks of shaded alleyways where people could keep cool during summer. But the rapid construction of high-rises and decreasing green spaces have made one of the fastest-growing cities in the world increasingly stifling. Subsidy cuts have brought about a rise of 18 to 42 per cent in electricity costs, affecting many poor residents’ options for cooling down. If Korea is so high-tech, what’s with the lack of air conditioning in a heatwave? Um Hamad, 41, works as a cleaner and lives with his family in a small flat in Musturad, in the city’s north. Though he considers them lucky to live on the relatively cool first floor, “in Cairo everything is suffocating”, he says. Hamad uses fans and water to keep cool inside, but the water bill is becoming expensive. “There’s always that trick of sleeping on the floor, and we wear cotton clothes,” he says. “The temperatures are harder to deal with for women who wear the hijab, so I always tell my daughters to wear only two layers and to wear bright colours.” In a tight-knit cluster of urban dwellings in Giza, to Cairo’s south, Yassin Al-Ouqba, 42, a train maintenance worker, lives in a house built from a mixture of bricks and mud-bricks. In August, he says, it becomes “like an oven”. “I have a fan and I place it in front of a plate of ice so that it spreads cold air throughout the room. I spread cold water all over the sheets.” And for parts of the world, the future looks utterly terrifying. New scientific research released last month predicts that the deadliest place on the planet for extreme heatwaves will be the North China Plain, one of the most densely populated regions in the world. The research, published in the peer-reviewed journal Nature Communications , shows that humid heatwaves with the capacity to kill even healthy people within hours could strike the area repeatedly towards the end of the century unless there are heavy cuts in carbon emissions. Heatwaves will make parts of China the deadliest places on Earth “This spot is going to be the hottest spot for deadly heatwaves in the future,” said Professor Elfatih Eltahir, of the Massachusetts Institute of Technology in the US, who led the study. The projections for the North China Plain – which encompasses all or large swathes of Shandong, Jiangsu, Anhui, Henan and Hebei provinces, as well as the municipalities of Beijing and Tianjin – are especially worrying because the region is a major food producer and home to 400 million farmers. Manila: ‘It gets hellish in summer’ In Manila, in the Philippines, where highs above 30 degrees are intensified by stifling humidity, air conditioning is a luxury even for those in medical care. The Dr Jose Fabella Memorial Hospital is said to have one of the world’s busiest maternity wards, with free contraception only recently made available in the predominantly Catholic country. An air-conditioned private room costs 650 Philippine pesos (US$12) per night, which is far beyond the means of most mothers-to-be, who end up in wards reliant on fans buzzing softly on wall mounts. “These fans work non-stop, 24 hours a day, so they never last a year,” says Maribel Bote, a nurse at the hospital for 28 years. The problem is compounded by regular overcrowding: in the maternity ward, known as ground zero of the country’s overpopulation crisis, as many as five mothers have been forced to share one bed. “It gets hellish in the summer – the fans blow hot air,” says Bote. “You’ll see the mothers using paper fans to cool themselves.” In Cambodia, which has seen devastating heatwaves and drought in recent years, surviving the heat is as much a question of status for prisoners as it is for civilians. In the early 2000s, Chao Sophea, 30, spent more than two years at Phnom Penh’s Prey Sar prison after being convicted on drug charges, which she denies. At the time, she was three months pregnant; Chao Sophea’s child spent its first year in an overcrowded cell designated for pregnant women and new mothers. We slept like smoked fish on a skewer. There was no air conditioning, not even a fan Former Prey Sar prisoner “It was actually a steaming room,” says Chao Sophea today. “I was using a fan made of a palm leaf to cool my baby down – that was what I could afford. There was a tiny hole in the wall, but can you imagine how much air you would absorb in such a crowded space? We made a request for an electric fan, but it never arrived.” An environmental activist who wishes to remain anonymous says he shared a cell of about four square metres with at least 25 other men when he was held in Prey Sar’s men’s wing earlier this year. “We slept like smoked fish on a skewer. There was no air conditioning, not even a fan.” Others may be able to secure better conditions. A 2015 report by the Cambodian League for the Promotion and Defence of Human Rights stated that “some prisons reportedly house ‘VIP cells’ for well-connected prisoners or those able to pay for single-cell accommodation”, and these are believed to be air-conditioned. Compounding the threat posed by the changing climate is the refugee crisis. The two are intimately linked, with extreme weather events often a factor in social, political and economic instability. A paper published in the journal Science in December found that if greenhouse gas emissions were not meaningfully reduced, global asylum applications would increase by almost 200 per cent by the end of the century. It’s suffocating. We soak the towels and try to breathe through them Hamda Al-Marzouq, Zaatari camp resident On a plain north of Amman, the capital of Jordan, some 80,000 Syrians live in the Zaatari refugee camp, a semi-permanent urban settlement set up six years ago and now considered Jordan’s fourth-largest city. Hamda Al-Marzouq, 27, arrived three years ago, fleeing airstrikes on her neighbourhood on the outskirts of Damascus. Her husband had gone missing during the war, and she was desperate to save her young son and extended family. Eight of them now live in a prefabricated shelter, essentially a large metal box, which Al-Marzouq says turns into an oven during the summer. “It’s a desert area, and we’re suffering,” she says by phone from the camp. “We have different ways of coping. We wake in the early morning and soak the floor with water. Then we sprinkle water on ourselves.” There is no daytime electricity, so fans are useless. When power does arrive at night, the desert has already cooled. Many days, her family will wait until the evening to walk outside, wrapping wet towels around their heads. But the biggest problem are sandstorms, which can arrive violently during summer months and engulf the camp for days. “We have to close the caravan windows,” she says, adding the room then gets hotter. “It’s suffocating. We soak the towels and try to breathe through them.” Al-Marzouq’s five-year-old son suffers respiratory problems and keeps getting infections, while asthma is rife across the camp. Water has also been an issue, with demand in northern Jordan – one of the most water-scarce countries in the world – surging following the refugee arrivals. A Unicef-led operation will see all households connected to a water network by October, which Al-Marzouq says has been a significant help. “We used to collect water with jerrycans and had to carry it for long distances. Now, with the water network being operational, things are much easier. We don’t have to fight in a long queue to get our share of water. Now there is equity.” A plan for the future? Across the board, lack of equality has been found to feed the urban furnaces. The US researchers who in 2013 uncovered the racial divide in urban heat vulnerability discovered that the more segregated a city was, the hotter it was for everyone. Rachel Morello-Frosch, one of the co-authors, told the Los Angeles Times at the time that “this pattern of racial segregation appears to increase everyone’s risk of living in a heat-prone environment”. Treating cities as a whole, ghettos and all, is a more effective way to tackle extreme urban heat, they found. Researchers recommended planting more trees and increasing light-coloured surfaces to reduce the overall heat island effect, adding that urban planning to mitigate future extreme heat “should proactively incorporate an environmental justice perspective and address racial/ethnic disparities”. Working to break social isolation, says Benmarhnia, “is a win-win situation”, with the added benefit of bringing the “invisible” people most at risk – like the homeless and illegal immigrants – back into the community, where they can be looked after. In at least one of the world’s hottest countries, steps are starting to be taken. India recently announced that a series of common-sense public health interventions have led to an enormous reduction in heat-related deaths – from 2,040 in 2015, to a little more than 200 in 2017. Successful measures included unlocking the gates to public parks during the day, distributing free water and painting the roofs of slum communities white, knocking 5 degrees off internal temperatures. Montreal first implemented a similar heat action plan in 2004, reducing mortality on hot days by 2.52 deaths per day, but as the heatwaves intensify, it is likely that this will need to be reassessed. Nadler says the devastating impacts of global warming are only just beginning to dawn on everyone. “Cities will have to rethink how we prepare for these emergencies and what we’re able to offer to all of our citizens – from the most affluent, to the most vulnerable.” The Guardian With reporting from Ruth Michaelson and Adham Youssef in Cairo, Oliver Holmes in Jerusalem, Carmela Fonbuena in Manila, Holly Robertson in Phnom Penh and Sam Wainwright in Hong Kong.