2019-09-01 Rolling Stone

September 2019 | Rolling Stone | 79

the Earth’s climate system. As the atmosphere

warms, the temperature difference between the

poles and the subtropics is shrinking, which is

changing the path of the jet stream, the big river

of wind 35,000 feet up in the sky that drives

our weather system. The jet stream’s path is

shaped by atmospheric waves called Rossby

waves, which are created naturally as the Earth

spins. Mann explains that as the Earth’s tempera-

ture gradient flattens, the Rossby waves tend to

bend, resulting in a curvy jet stream that is more

likely to get “stuck,” trapping weather systems

in place and creating what Mann calls “huge

heat domes.”

Extreme heat is already transforming our

world in subtle and not-so-subtle ways. Disney

executives recently voiced concern that rising

temperatures will significantly reduce the num-

ber of visits to their parks. In Germany, officials

were forced to put a speed limit on the autobahn

because of fears the road would buckle from

heat. The U.S. military has already incurred as

much as $1 billion in costs during the past decade

— from lost work, retraining, and medical care

— due to the health impacts of heat. The warm-

ing of the planet “will affect the Department of

Defense’s ability to defend the nation and poses

immediate risks to U.S. national security,” a re-

cent DOD report said. Forests and soils are dry-

ing out, contributing to explosive and unprece-

dented wildfires. Habitation zones for plants and

animals are changing, forcing them to adapt to a

warmer world or die. A U.N. report found that

1 million species are at risk of extinction in the

coming decades. Another study by researchers

at MIT suggests that rising temperatures and hu-

midity may make much of South Asia, including

parts of India and Pakistan, too hot for human

existence by the end of the century. As scien-

tist Peter Gleick, co-founder of the Pacific Insti-

tute in California, told me, “There is a shocking,

unreported, fundamental change coming to the

habitability of many parts of the planet, includ-

ing the USA.”

Since the Industrial Revolution, the Earth’s

temperature has risen by 1.8°F (1°C). As we burn

more fossil fuels, the warming is accelerating.

The planet’s average surface temperature in

2018 was the fourth-highest since 1880, when

record-keeping began. Gavin Schmidt, a cli-

mate scientist at NASA, said there’s a “90 per-

cent chance” that 2019 will turn out to be even

hotter. Nine of the 10 warmest years in recorded

history have occurred since 2005. This past June

was the hottest June ever recorded. Astonishing-

ly, July was the hottest month in human history.

But warming is not happening at the same rate

everywhere. The Arctic, for example, is warm-

ing twice as fast as the rest of the world. Why?

It’s a classic climate feedback loop: Ice and snow

are highly reflective, bouncing sunlight back into

space. But as the region warms, sea and land ice

declines, exposing more open land and ocean,

which are darker and absorb more heat. As tem-

peratures rise, the permafrost melts, which re-

leases methane, a potent greenhouse gas, which

further accelerates the melting. Greenland is in

the midst of one of the biggest melt seasons ever

recorded, with temperatures as much as 40°F

above normal. And as the Arctic heats up and

dries out, it burns. There have been unprece-

dented wildfires this year, with more than 100

massive fires raging across the region since June.

The burning peat has already emitted more than

100 million tons of greenhouse gases (nearly the

annual carbon emissions of Belgium), further ac-

celerating the climate feedback cycle that’s cook-

ing the planet.

But the greatest risk to human health may be

in areas that are already hot, where tempera-

ture increases will strain habitability. In the U.S.,

the fastest-warming cities are in the Southwest.

Las Vegas, El Paso, Tucson, and Phoenix have

warmed the most, each by at least 4.3°F since

1970. Globally, many of the hottest cities are in
      India. In May, a deadly heat wave sent tempera-
      tures above 120°F in the north. The desert city of
      Churu recorded a high of 123°F, nearly breaking
      India’s record of 123.8°F, set in 2016. There were
      warnings not to go outside after 11 a.m. Author-
      ities poured water on roads to keep them from
      melting. A 33-year-old man was reportedly beat-
      en to death in a fight over water. The preliminary
      death toll in India for this summer’s heat wave is
      already more than 200, and that number is like-
      ly to grow.
      How hot will it get? That depends largely
      on how far and how fast carbon-dioxide levels
      rise, which depends on how much fossil fuel
      the world continues to burn. The Paris Climate
      Agreement (which President Trump pulled the
      U.S. out of ) aims to limit the warming to 3.6°F
      (2°C). Given the current trajectory of carbon pol-
      lution, hitting that target is all but impossible.
      Unless nations of the world take dramatic ac-
      tion soon, we are headed for a warming of at
      least 5.4°F (3°C) by the end of the century, mak-
      ing the Earth roughly as warm as it was 3 mil-
      lion years ago during the Pliocene era, long be-
      fore Homo sapiens came along. “Human beings

TOO HOT TO HANDLE

Volunteers distribute water on a

sweltering day in Phoenix, where the

average temperature is rising faster

than in almost every other American

city. There were 181 heat-related deaths

in Arizona’s Maricopa County last year.

CL

OC

KW

ISE

FR

OM

TO

P:^

MA

TT

M
AW

SO

N/
GE

TT

Y^ I

MA

GE

S;^

RA

LP

H^ F

RE

SO

/G

ET

TY

IM

AG

ES

;^ C

AI

TL

IN

O

’H

AR

A