Punishing heatwaves are making the headlines again, raising questions as to whether the planet is getting too hot for humans to enjoy a reasonable quality of life. For millions of mostly underprivileged people, it already has, and they don’t. The good news is that humans — at least some of us — can survive extreme heat. The bad news is that it’s tough.

In Uninhabitable Earth: Life After Warming, David Wallace-Wells describes a situation that is ‘much, much worse than you think’.  But while the debate is typically focused on how the inhabitants of previously comfortable places will have to begrudgingly adapt, people in countries such as Egypt came to terms with heat long ago. They know it is an adversary that wins in the end, and meanwhile demands constant concessions. The rich stave it off with air conditioning; the poor keep to the shady side of the street.

Only around five per cent of Egypt is arable land flanking the Nile, where most of the population (now 100 million) has always lived. The rest is empty desert, a rocky matrix reverberating heat like a convection oven. In Cairo, the world’s oldest desert megacity (population more than 20 million), summer begins in April and only loosens its grip in October. Although recorded temperatures hover in the low 100 degrees F (high 30s °C), it feels warmer owing to the profusion of cars, buildings and air conditioner compressors. In Upper Egypt, summertime temperatures of 110 -115 °F (43-46 °C) are the norm through to November, and days exceeding 120 °F (nearly 49 °C) are common. But only the uninitiated measure heat with a thermometer; people who deal with it daily have more pressing concerns, like praying they will last until sunset. At 90°F, (32 °C) the mind slows and by 105°F (40 °C) it meanders to a near halt. At that point, it’s automatic pilot.

Heat endurance is a humbling process with metaphysical implications. The ancient Egyptians referred to their sun god, Amun-Ra, as ‘the fierce, red-eyed lion’. They had felt his fangs, lived and died at the mercy of his gnawing attentions. A creative yet implacable force, Ra was omniscient, seeing all, never blinking, a burning hole in an empty sky, one glaring, lidless day after the next. Trapped in a body, longing for the cool indifference of divinity, Egyptians invented eternity and paradise but, tellingly, not a fiery hell; there was enough of that already. Although Thebes in the south was the centre of temple wealth and ritual that required the pharaohs’ frequent presence, many resided with their families in the cooler north, and spent time on their royal barges going back and forth, enjoying the refreshing Nile breeze.

Average people lived in mud brick huts as close to the river as possible, and whoever had a roof slept on it in summer. Wet reed mats were attached to windows and doorways, and water-filled clay pots placed on the floor to soften the hot abrasive wind. Men worked in the nude or a loin-cloth, and otherwise went bare-chested with wraparound skirts. Women wore tube dresses, sometimes with a central strap leaving the breasts uncovered, sometimes with shoulder straps that lightly concealed them. During the brief winter, the better-off could throw on a wool cloak, but shoes were uncalled for, only sandals, some with the toe curling upwards like a ship’s prow. Rich and poor shaved their heads to keep cool but for their outings they wore wigs, elaborately coiffed and bejeweled real-hair ones for the rich, and shoulder-wide brown wool ones for everyone else.

Heat can be instructive. Thus, Cairo’s medieval merchants invented ‘air-conditioned malls’, that is, canvas-covered bazaars, whose fragrant shade encouraged commerce, as did the donkey taxis waiting nearby to carry shoppers and their purchases swiftly home. Buildings were equipped with simple but effective wind-catchers or ventilators, a tall wooden shaft installed on the roof, its open side facing north or north-west to channel air downwards to lower floors. Courtyard gardens and fountains took the edge off the heat for wealthy city-dwellers, as did lofty ceilings, sometimes ten or more metres high. The poor frequented public baths, drank at public fountains, and paid to have buckets of water carried to their homes.

Then as now, water was everything; a low Nile flood meant instant drought and famine. Low floods triggered wheat-hoarding, which typically resulted in price-gauging and civil unrest. Nowadays, the reservoir of the Aswan High Dam (Lake Nasser) may help mitigate the effects of drought in the short term, but in the long term it has proved disastrous for the food production it was meant to augment. Egypt is today the world’s biggest importer of wheat, traditionally purchased largely from Russia and Ukraine.

In summer, Cairo’s elite flee the sweltering city for their second or third homes on the Mediterranean and Red Sea coasts that are usually empty the rest of the time. Millions of average Cairenes, who will rarely, if ever, visit their country’s beaches, live year-round in tightly packed informal housing (unlicensed brick buildings). Wide streets are rare in these quarters; narrow dirt paths run around buildings, with few windows, that in summer are stiflingly hot. Electricity and water are often pirated from city lines. Garbage is sporadically collected and the acrid stench of burning plastic saturates the air. Ordinary life for the urban bulk of Egypt’s population is no walk in the park; in the sprawling capital, parks are few.

Heat shapes behaviour, sharpening the distinction between necessary and unnecessary actions. Most, as it turns out, fall into the latter category. Heat teaches calm determination, for example, during power outages that may last minutes, or excruciating hours. Almost everyone has a fan, the bare minimum, and the roughly 80 per cent of Egyptian households with sufficient running water still need electric pumps to deliver it to their taps. When the power goes down, no one panics; households store water in jerrycans for such occasions. Wetting the head or keeping a moist cloth on the back of the neck is recommended, as is sitting still.

A time-honoured torture method is to tie someone out in the sun, and Egypt has been out there for ages, a fact not without political ramifications. Say you are oppressed by your government, forbidden basic freedoms, denied justice, and obliged to labour for derisive pay, substandard housing, and limited amounts of water and food. You are outraged, your dignity demands action. But action requires energy and you haven’t got any, or else just enough to get by. Besides, anger engenders heat and is therefore self-defeating. Autocracies like it hot, to a point.

Egypt’s leaders have wisely fostered investment in the world’s biggest solar park, knowing that as the population grows larger, water scarcer and the weather hotter, pressure on the electricity grid translates into political pressure; its failure is their failure. Power shortages hit where it hurts most, in the body’s ability to do work, and in the minds of people struggling to rationalise their existence. Egypt’s youth, its largest demographic (with 60 per cent under age 30), is a virtual tinderbox of thwarted hopes that under continued stress could spontaneously combust. The state’s commitment to alternative energy is born of the need to maintain control, and keep its own A/Cs on full blast.

Frigidly air-conditioned homes, cars and offices signal status in places such as Egypt, but while the elite may reduce exposure, heat is still at work, nature’s reminder that everyone must bend the knee. Ask the experts in Cairo. They will tell you it’s a power only fools fail to heed, a bit like a wrathful god.