GSN_May_FINAL_Yumpu

to pelicans and hurricanes while
Antarctica is freezing, white, and
home to penguins and blizzards.
Yet as soon as science confirmed
that seas are rising because human
actions are warming the atmosphere,
researchers knew Antarctica
would be critical to the future
of coastal communities, especially
the already sinking coast of Louisiana.
Atmospheric warming is raising
sea levels in two ways. First, water
expands as it is warmed, and the
oceans have been increasing in
volume because of that. Second,
water stored as ice in glaciers and
ice shelves is now pouring into the
oceans, further increasing their
volume. Antarctica holds 90 percent
of the world’s ice. Suddenly
an isolated, little-visited continent
became very, very important to
Louisiana, and the world.
Stretched across the bottom of
the planet, Antarctica is huge,
covering an area roughly the size
of the United States and Mexico
combined. Heaped on top of that
vast land mass is ice averaging
7,000 feet in depth. Imagine a vast
container of water with a faucet at
the bottom.
If the faucet only drips, it won’t
change ocean levels much. But
if opened wider and fixed in that
position for centuries, most coastlines
would drown. If all the ice
in Antarctica melts, those same
models show the oceans rising 200
feet, meaning Baton Rouge, Louisiana,
now 80 miles north of New
Orleans, would be on what’s left of
the coast. Evidence has long existed
that past episodes of dramatic
increases in sea level were accompanied
by sudden, huge losses of
Antarctic ice. But the new and rapidly
evolving science focusing on
the complex forces at work on that
continent had yet to nail down reliable
mechanisms for the progression
of ice loss.
While our planet has been
warming, the floating ice fields
surrounding Antarctica have been
growing in size in recent years.
31
These floating fields, composed
of relatively recent snows, serve
as bumpers protecting the massive
land-based ice shelves from
the warming ocean. They were one
reason the United Nations’ Intergovernmental
Panel on Climate
Change said Antarctica would
contribute little to the group’s
“worst case” rise of 3.2 feet by the
end of the century.
That was shaken in January
with the publication of a study
titled “Contribution of Antarctica
to past and future sea level rise.” 4
Researchers Robert DeConto and
David Pollard had been struggling
for years to determine why their
computer models could not reproduce
the dramatic melting that
occurred 125,000 years ago under