The Guardian - Jonathan Watts | Elle Hunt
It is the temperature at which human cells start to cook, animals suffer and air conditioners overload power grids. Once an urban anomaly, 50C is fast becoming reality
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In a city at 50C, the only people in sight are those who do not have access to air conditioning.
Illustration: Kevin Whipple
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Imagine
a city at 50C (122F). The pavements are empty, the parks quiet, entire
neighbourhoods appear uninhabited. Nobody with a choice ventures outside
during daylight hours. Only at night do the denizens emerge, HG
Wells-style, into the streets – though, in temperatures that high, even
darkness no longer provides relief. Uncooled air is treated like
effluent: to be flushed as quickly as possible.
School playgrounds are silent as pupils shelter inside. In the
hottest hours of the day, working outdoors is banned. The only people in
sight are those who do not have access to air conditioning, who have no
escape from the blanket of heat: the poor, the homeless, undocumented
labourers. Society is divided into the cool haves and the hot have-nots.
Those without the option of sheltering indoors can rely only on
shade, or perhaps a water-soaked sheet hung in front of a fan.
Construction workers, motor-rickshaw drivers and street hawkers cover up
head to toe to stay cool. The wealthy, meanwhile, go from one
climate-conditioned environment to another: homes, cars, offices,
gymnasiums, malls.
Asphalt heats up 10-20C higher than the air. You really could fry an
egg on the pavement. A dog’s paws would blister on a short walk, so pets
are kept behind closed doors. There are fewer animals overall; many
species of mammals and birds
have migrated to
cooler environments, perhaps at a higher altitude – or perished.
Reptiles, unable to regulate their body temperatures or dramatically
expand their range, are
worst placed to adapt. Even insects suffer.
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| Melting asphalt cause road markings to distort in New Delhi |
Maybe in the beginning, when it was just a hot spell, there was a
boom in spending
as delighted consumers snapped up sunglasses, bathing suits, BBQs,
garden furniture and beer. But the novelty quickly faded when relentless
sunshine became the norm. Consumers became more selective. Power grids
are overloaded by cooling units. The heat is now a problem.
The temperature is recalibrating behaviour. Appetites
tend to fade as the body avoids the thermal effect of food and
tempers are quicker to flare
– along, perhaps, with crime and social unrest. But eventually lethargy
sets in as the body shuts down and any prolonged period spent outdoors
becomes dangerous.
You could see the physical change. Road surfaces started to melt …
Dev Niyogi, American Meteorological Society
Hospitals see a surge in admissions for heat stress, respiratory
problems and other illnesses exacerbated by high temperatures. Some set
up specialist wards. The elderly, the obese and the sick are most at
risk. Deaths rise.
At 50C – halfway to water’s boiling point and more than 10C above a
healthy body temperature – heat becomes toxic. Human cells start to
cook, blood thickens, muscles lock around the lungs and the brain is
choked of oxygen. In dry conditions, sweat – the body’s in-built cooling
system – can lessen the impact. But this protection weakens if there is
already moisture in the air.
A so-called “wet-bulb temperature” (which factors in humidity) of
just 35C can be fatal after a few hours to even the fittest person, and
scientists
warn climate change will make such
conditions increasingly common in India, Pakistan, south-east Asia and
parts of China. Even under the most optimistic predictions for emissions
reductions,
experts say almost half the world’s population will be exposed to potentially deadly heat for 20 days a year by 2100.
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| A motorcyclist is sprayed with water in Karachi |
Not long ago, 50C was considered an anomaly, but it is increasingly
widespread. Earlier this year, the 1.1 million residents of Nawabshah,
Pakistan, endured the hottest April ever recorded on Earth,
as temperatures hit 50.2C. In neighbouring India two years earlier, the town of Phalodi
sweltered in 51C – the country’s hottest ever day.
Dev Niyogi, chair of the Urban Environment department at the American
Meteorological Society, witnessed how cities were affected by extreme
heat on a research trip to New Delhi and Pune during that 2015 heatwave
in India, which
killed more than 2,000 people.
“You could see the physical change. Road surfaces started to melt,
neighbourhoods went quiet because people didn’t go out and water vapour
rose off the ground like a desert mirage,” he recalls.
“We must hope that we don’t see 50C. That would be uncharted
territory. Infrastructure would be crippled and ecosystem services would
start to break down, with long-term consequences.”
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| Hajj pilgrims in Mecca are sprayed with cool water |
Several cities in the Persian Gulf are getting increasingly accustomed to such heat. Basra – population 2.1 million –
registered 53.9C two years ago.
Kuwait City and
Doha have experienced 50C or more in the past decade. At Quriyat, on the coast of
Oman, overnight temperatures earlier this summer remained above 42.6C, which is
believed to be the highest “low” temperature ever recorded in the world.
At Mecca, the two million hajj pilgrims who visit each year need ever more sophisticated support to beat the heat.
On current trends, it is only a matter of time before temperatures exceed the record 51.3C reached in 2012. Last year, traditionalists were
irked by plans to install what are reportedly the
world’s biggest retractable umbrellas to provide shade on the courtyards and roof of the Great Mosque. Air conditioners weighing
25 tonnes
have been brought in to ventilate four of the biggest tents. Thousands
of fans already cool the marble floors and carpets, while police on
horseback spray the crowds with water.
The blast of furnace-like heat ... literally feels life-threatening and apocalyptic
Professor Nigel Tapper
Football supporters probably cannot expect such treatment at the
Qatar World Cup in 2022, and many may add to the risks of hyperthermia
and dehydration by taking off their shirts and drinking alcohol. Fifa is
so concerned about conditions that it has moved the final from summer
to a week before Christmas. Heat is also why Japanese politicians are
now debating whether to introduce daylight saving time for the 2020
Tokyo Olympics so that marathon and racewalk athletes can start at what
is currently 5am and avoid mid-afternoon temperatures that recently
started to pass 40C with humidity of more than 80%.
At the Australian open in Melbourne this year – when ambient temperatures reached 40C – players were staggering around like
“punch-drunk boxers”
due to heatstroke. Even walking outside can feel oppressive at higher
temperatures. “The blast of furnace-like heat ... literally feels
life-threatening and apocalyptic,” says Nigel Tapper, professor of
environmental science at Melbourne’s Monash University, of the 48C
recorded in parts of the city. “You cannot move outside for more than a
few minutes.”
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| French tennis player Alize Cornet falls to the ground suffering from the heat during the Australian Open |
The feeling of foreboding is amplified by the increased threat of
bush and forest fires, he adds. “You cannot help but ask, ‘How can this
city operate under these conditions? What can we do to ensure that the
city continues to provide important services for these conditions? What
can we do to reduce temperatures in the city?’”
Those
places already struggling with extreme heat are doing what they can. In
Ahmedabad, in Gujarat, hospitals have opened specialist heat wards.
Australian cities have made swimming pools accessible to the homeless
when the heat creeps above 40C, and instructed schools to cancel
playground time. In Kuwait, outside work is forbidden between noon and
4pm when temperatures soar.
But many regulations are ignored, and companies and individuals
underestimate the risks. In almost all countries, hospital admissions
and death rates tend to rise when temperatures pass 35C – which is
happening more often, in more places. Currently, 354 major cities
experience average summer temperatures in excess of 35C; by 2050,
climate change will push this to 970, according to
the recent “Future We Don’t Want” study
by the C40 alliance of the world’s biggest metropolises. In the same
period, it predicts the number of urban dwellers exposed to this level
of extreme heat will increase eightfold, to 1.6 billion.
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| Workers take a break at a building site in Kuwait City, where work is forbidden between noon and 4pm |
As baselines shift across the globe, 50C is also uncomfortably near
for tens of millions more people. This year, Chino, 50km (30 miles) from
Los Angeles, hit a record of 48.9C,
Sydney saw 47C, and Madrid and Lisbon also experienced temperatures in the mid-40s. New studies suggest France
“could easily exceed”
50C by the end of the century while Australian cities are forecast to
reach this point even earlier. Kuwait, meanwhile, could sizzle towards
an uninhabitable 60C.
How to cool dense populations is now high on the political and
academic agenda, says Niyogi, who last week co-chaired an urban climate
symposium
in New York. Cities can be modified to deplete heat through measures to
conserve water, create shade and deflect heat. In many places around
the world, these steps are already under way.
The city at 50C could be more tolerable with lush green spaces on and
around buildings; towers with smart shades that follow the movement of
the sun; roofs and pavements painted with high-albedo surfaces; fog
capture and renewable energy fields to provide cooling power without
adding to the greenhouse effect.
But with extremes creeping up faster than baselines, Niyogi says this
adapting will require changes not just to the design of cities, but how
they are organised and how we live in them. First, though, we have to
see what is coming – which might not hit with the fury of a flood or
typhoon but can be even more destructive.
“Heat is different,” says Niyogi. “You don’t see the temperature creep up to 50C. It can take people unawares.”
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