Geoscience Reference
In-Depth Information
11
Antarctica: a global change
perspective
ALAN RODGER
The natural world is the greatest source of excitement; the greatest
source of visual beauty; the greatest source of intellectual interest.
It is the greatest source of so much in life that makes life worth
living.
David Attenborough
Antarctica has been separated from the other continents for at least 30million
years. It is largely a frozen, barren continent with over 99% of its surface covered by
ice, up to 4.5 km thick. It is the highest, driest, windiest and coldest continent and
has the least vegetation and terrestrial life both in quantity and diversity. By
complete contrast the Southern Ocean that surrounds Antarctica is rich in marine
life, supporting many iconic species, including whales, seals, penguins and
albatrosses. Antarctica has provided a remarkably stable environment over recent
geological time and hence the physiological functions of many of its native marine
species are now extremely sensitive to very modest changes in temperature.
Antarctica is therefore considered to be one of the most fragile areas on Earth,
and therefore most vulnerable to the effects of climate change.
Antarctica is at the very end of the Earth, yet human activity is having a
signi
cant impact on its environment. Changes in atmospheric circulation arising
from the impacts of humans elsewhere are causing regional effects such as the break-
up of ice shelves, marked changes in sea ice concentrations in the southern Paci
c
Ocean and Ross Sea areas, and reductions in krill concentrations in the South
Atlantic. These are all associated with increased carbon dioxide emissions and the
effects of the Antarctic ozone hole.
But what happens in Antarctica has global signi
cance too. The most obvious
examples are the melting of the ice, which contributes signi
cantly to sea level rise,
and changes in ocean circulation, responsible for moving 90% of the heat around the
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