September 2019 | Rolling Stone | 81
HOTTER AND HOTTER
July 2019 was the hottest month on the planet, in more than 100 years of record-keeping. Below
is a snapshot of one of the hottest days in the U.S., when virtually the entire country was sweltering.
“This is not your grandfather’s summer,” said U.N. Secretary-General António Guterres.This phenomenon, which is called Urban Heat
Island Effect, impacts most cities in the world.
On average, cities are 2 to 5°F warmer than their
leafy suburbs during the day — and as much as
22°F warmer during some evenings. The effect is
so pervasive that some climate skeptics have se-
riously claimed that global warming is merely an
illusion created by thousands of once-rural me-
teorological stations becoming surrounded by
urban development.
Counterintuitively, the biggest health effects
of rising heat often occur at night, when vulner-
able people such as the elderly badly need the
chance to cool down. Without that chance, they
can succumb to heatstroke, dehydration, and
heart attacks. This appears to be what happened
during the heat wave that hit Europe in 2003,
killing 70,000 people, mostly in buildings with-
out air conditioning. Research has shown that
the cause of many deaths was not so much the
104°F daytime temperatures, but the fact that
nights stayed in the seventies or higher.
To reduce the heat-absorbing impacts of
urban areas, some cities are experimenting with
white roofs. The idea is to change the reflectiv-
ity of the rooftop to bounce more light off so that
the building absorbs less heat. New York, for in-
stance, introduced rules on white roofs into its
building codes as long ago as 2012. Volunteers
and workers have taken white paint to 10 mil-
lion square feet of roofs in the city, though that
is still less than one percent of New York’s total
roof area.
Keith Oleson of the National Center for Atmo-
spheric Research in Boulder, Colorado, looked
at what might happen if every roof in large cities
around the world were painted white. He found
it could decrease the Urban Heat Island Effect by
a third — enough to reduce the maximum day-
time temperatures by about 1°F, and even more
in hot, sunny regions such as the Arabian Penin-
sula and Brazil.
In Los Angeles, city officials are experiment-
ing with asphalt sealants that give roads a light-
reflective surface. Manufacturers claim they can
reduce the surface temperature by up to 30°F.
Greg Spotts, chief sustainability officer in the
Los Angeles Bureau of Street Services, says the
sealants have worked well so far, but cost (it’s
roughly three times more expensive than con-
ventional sealant) and questions about durabil-
ity have limited their use. Spotts estimates that
of the 23,000 miles of streets in L.A., less than
10 miles have been covered with reflective coat-
ing. “But we know it works, because dogs always
move over to walk on the white streets when
they can,” says Spotts.
Other places, such as Stuttgart, Germany, are
trying to re-engineer the airflow of the whole
city. Stuttgart is an industrial town surround-
ed by steep hills at the bottom of a river valley,
where heat and polluted air linger. To help cool
things off, city planners have built a number of
wide, tree-flanked arterial roads that work as
ventilation corridors and help clean, cool air
flow down from the hills. Officials have also re-It will also require leadership from city and
state officials. A recent poll found that two-thirds
of Arizonans accept that climate change is hap-
pening, but most elected officials in the state, in-
cluding Republican Gov. Doug Ducey, are hardly
climate activists. Arizona is one of the sunniest
states in the nation, and yet only 6.5 percent of
the state’s electricity comes from solar power. A
statewide ballot initiative in 2018 to require 50
percent renewable power by 2030 was sound-
ly defeated, in part because the parent compa-
ny of Arizona Public Service, the big public util-
ity in the state, spent more than $37 million on
false and misleading arguments about how tran-
sitioning to renewable power would raise power
bills and destroy the Arizona economy.
“We have a large number of elected officials
who don’t believe in climate change, period,”
says Stacey Champion, a longtime Phoenix en-
ergy and climate activist. “How do you get effec-
tive, data-driven policy if you have people push-
ing hard against it because they are batshit crazy,
or they are afraid it will spook companies like
Nike who want to come here?”
But as the world heats up, cities will get the
worst of it. They are built of concrete and as-
phalt and steel, materials that absorb and am-
plify heat during the day, then radiate it out at
night. Air conditioners blow out hot air, exac-
erbating the problem of urban heat buildup.
Downtown Phoenix, for example, can be as
much as 21°F hotter than the surrounding area.HEAT WAVE | JULY 19TH, 2019EARTH’S INCREASING AVERAGE SURFACE TEMPERATURE1880 1900 1920 1940 1960 1980 2000 2020-0.50.00.51.0CREDIT: NASA/GISSCREDIT: NOAATEMPERATUREANOM
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