Ice with everything - Antarctica: Global Science from a Frozen Continent - page 67

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Ice with everything

VALÉRIE MASSON-DELMOTTE

Where does the strange attraction to the polar regions lie, so
powerful, so gripping that on one's return from them one forgets
all the weariness of body and soul and dreams only of going back?
Where does the incredible charm of these unattended and terri c
regions lie?

Jean-Baptiste Charcot, 1908

For many people the word Antarctica is synonymous with cold and with
more ice than can be imagined. The Antarctic continent has been continuously
covered by a thick layer of ice for the past 15million years, leaving less than 0.5% of
the underlying rock visible. This enormous mass of ice, formed by the progressive
accumulation of snowfall, slowly flows back to the ocean. Antarctica is a major

actor in our global climate system as well as being a most precious archive of
the history of climate evolution over the last 1million years.

Antarctic ice in the global water cycle

For many millions of years, Antarctica has been the largest reservoir of
continental ice on earth. The dimensions of this are astonishing.

The area permanently covered by continental snow and ice is greater than 13million
km², 30% more than all of Europe. Around Antarctica, the cold Austral Ocean
enhances the ice area every winter as the frozen surface waters form sea ice. These
ice surfaces re

' sleeping giant '

ect sunshine back into space rather than absorbing it, helping to
maintain extremely cold conditions at the high southern latitudes.
The Antarctic sea ice is marked by spectacular seasonal variations. When
the sea surface temperature drops below

1.8 C, it can freeze. However, winds and
changes in ocean water density can induce a vertical mixing which increases the