Popular Science - USA (2020 - Winter)

DYNAMIC DUO

SOUTH POLE, ANTARCTICA

PATCHWORK

SOLUTIONS

DISASTER: In 1985, British Antarc-

tic Survey researchers discovered

that the region’s level of ozone (O 3 ),

the atmospheric molecule that

shields earthlings from the sun’s

radiation, had plummeted 40

percent between 1977 and 1984.

The depleted air formed a “hole”

that stretched up to 11.6 million

square miles over the South Pole

by the early 2000s. The team

knew that the gas varied natu-

rally with sunspots, seasons, and

latitude, but this drop-off vexed

them. Experiments by chem-

ists in California revealed that

chlorine emitted from chloro-

fluoro carbons (CFCs), widely used

in refrigerants and aerosols since

the 1920s, was breaking down

ozone in the stratosphere at an

unprecedented rate.

COMEBACK: International govern-

ments acted swiftly once they saw

the data from chemists and me-

teorologists. In 1987, nearly 200

countries united to pass the Mon-

treal Protocol, a ban that forced

manufacturers to create CFC al-

ternatives that wouldn’t tamper

with ozone. It was a level of coop-

erative environmental action that

the world had never experienced

before— and hasn’t seen since.

Once humans stemmed the

flow of CFCs, the planet’s circula-

tory system took over. We needed

the help, says Susan Strahan, an

atmospheric scientist with the

NASA Goddard Space Flight

Center who’s spent her career

studying the ozone hole. “We

created these substances that

are not naturally occurring,” she

adds. “We can’t just go and suck

them back out.” Instead, rafts of

atmospheric wind deliver fresh

ozone from the tropics, where it

naturally forms, to the poles. As

a result of our drop in emissions

and this heavenly circulation, the

concentration of O 3 has spiked,

causing the “hole” to shrink to

3.9 million square miles in 2019.

Still, the combined power of

the CFC ban and the self- healing

atmosphere might not prevail

forever. Replacement chemicals,

such as the tetrafluoroethane gas

now used in car air conditioners,

have been found to contribute

to global warming. To counter,

companies are developing new

ozone- and climate- friendly for-

mulas, hinting at the possibility

of a future where we can cool our

roasting planet and still preserve

our protection from the sun’s rays.

105

RECOVERY INITIATED: 1987

PROGRESS: PARTIALLY COMPLETE