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SCIENCEMonday 2 November 2015

UN weather body: Antarctic ozone hole expands due to cold

JAMEY KEATEN Antarctic region were per- as refrigerants and aerosol the overall trend toward NASA’s Newman said the
Associated Press sisting longer than usual, cans released chlorine and that goal. particularly strong El Nino
GENEVA (AP) — The Antarc- and that unusually weak bromine that destroyed “There is no need for undue this year was “the first thing
tic ozone hole has swelled vertical energy flows were ozone molecules high in alarm because we are on that comes to your mind”
this month to one of its big- among major contributors the air. a course to recovery, but but added there was no
gest sizes on record, U.N.
and U.S. scientists say, insist- This image provided by NOAA shows the ozone hole. we have not observed it Associated Press
ing that the Earth-shielding yet,” said WMO scientist evidence yet of any con-
ozone layer remains on to the exceptionally large A widely hailed internation- Geir Braathen, who wrote nection between that and
track to long-term recovery hole. al accord in 1987 to phase the bulletin. “CFCs (chloro- the larger ozone hole, and
but residents of the south- The stratospheric ozone out use of ozone-deplet- fluorocarbons), they have a scientists will need time
ern hemisphere should be layer, which sits some 25 ing chemicals has under- long life in the atmosphere to explore the possible
on watch for high UV levels kilometers (18 miles) high pinned hopes for recov- ... many, many decades. It causes. He also said NASA
in the weeks ahead. and protects against harm- ery of stratospheric ozone takes a long time for these model simulations have
The World Meteorological ful UV rays, is different from worldwide by 2070. WMO molecules to get out of the generally turned up very
Organization, in a regular the ground level ozone that and NASA say the hole had atmosphere.” little effect on the Antarc-
bulletin released Thursday, is a harmful pollutant. The been leveling off and even “We are suffering now from tic ozone hole from climate
said the Antarctic ozone ozone layer had been thin- shrinking a bit, and hope the sins of the past,” he change and an increase in
hole often faces seasonal ning since the late 1970s this year’s one-off expan- added. heat-trapping greenhouse
and year-to-year varia- because man-made chlo- sion of the ozone hole will gases in the atmosphere.q
tions, rofluorocarbons often used have little to no impact on
but says the expansion this
year shows “we need to re-
main vigilant.”
The Geneva-based U.N.
agency pointed to NASA
data on Oct. 2 showing the
hole had reached 28.2 mil-
lion square kilometers (10.9
million square miles) — larg-
er than the size of Russia
and Canada put together.
It was the largest recorded
on that date, and the hole
has remained at a record
size on the dates since,
WMO said.
According to NASA, the
record largest ozone hole
dates to Sept. 9, 2000, when
it was 29.9 million square ki-
lometers.
Paul Newman, chief sci-
entist for earth sciences at
NASA’s Goddard Space
Flight Center in Greenbelt,
Maryland, said prolonged
wintertime conditions in the