Time_USA_-_23_09_2019

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ANTARCTICA


5.4 MILLION SQ. MILES


CONTIGUOUSU.S.


3.1 MILLION SQ. MILES


Summer ice

Winter ice

GIGATONNES


SINCE 1992


MM


TOTAL


SEA LEVEL


RISE


CUMULATIVE


CHANGE IN


ICE MASS


From
thermal
expansion

From
added
water

1993 2000 ’05 ’10 ’15 2017


1992 ’95


-3,000


-2,000


-1,000


0


1,000


2000 ’05 ’10 ’15 ’17


0


20


60


80


Continental imbalance
Antarctica’s ice grows and shrinks
seasonally. But, particularly in
western regions, ice is melting faster
than it is accumulating

Behind earth’s rising seas


THE EXTENT


Antarctica’s
area roughly
doubles each
winter from
coastal sea
ice

SWELLING WATERS


Carbon dioxide traps
heat, which melts
polar ice and raises
ocean temperatures.
Water expands as it
warms, further raising
sea levels


WHAT’S MELTING


Seas may rise 1 m in
100 years. Antarctica is
melting slower than the
Arctic, but it has more
ice. Here are sea-level
gains if all the glaciers
melted

THE LOSSES


Antarctic ice melt has accelerated.
The rate of recent ice loss is five
times the rate of 20 years ago

THE DEPTH


The deepest ice
is 3 miles thick,
the height of
11 Empire
State Buildings

73 m

Antarctica’s
glaciers

6 m

Greenland’s
glaciers

0.6 m

Nonpolar
glaciers

0.12 m

Alaska’s
glaciers
49 gigatonnes
of ice shed annually
from 1992 to 1997

219 gigatonnes
of ice shed annually
from 2012 to 2017

Collapse
The ice shelves
break apart.
This does
not raise sea
levels, as the
ice was already
in the water

Acceleration
But with no
resistance from
the ice shelf,
glacier ice flows
faster, falls
into the ocean
and raises sea

3


4


Ð2,324


gigatonnes

SOURCES: NOAA NCWCP LABORATORY FOR SATELLITE ALTIMETRY; NASA; USGS; NSIDC; IMBIE; NSF; SCIENTIFIC AMERICAN;


ANDREW SHEPHERD, UNIVERSITY OF LEEDS; THEODORE SCAMBOS, UNIVERSITY OF COLORADO BOULDER

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