Canada, Greenland, at the North Pole, and here on the Antarctic
Peninsula.
One way that we know there is more heat-trapping CO2 in our
atmosphere today than at any time in at least the past 420,000 years is
through ice-core samples taken from Siple Dome, Vostok, and other
sites in the Antarctic interior. These ice cores contain trapped bubbles
of ancient air that have been isolated, dated, and chemically analyzed.
They also show that climate is far less stable than we have imagined,
and that the past 10,000 years—the period that has seen the rise of
human civilization—has also been a period of atypical climate stability.
“Climate’s a dangerous beast and we’re poking it with a sharp stick,” is
how one scientist described our contribution of industrial carbon to
the atmosphere.
Rapid warming in the Antarctic Peninsula over the last 50 years,
including an incredible 10°F rise during the austral winter months, has
led to a decline of winter sea ice that krill depend on for their produc-
tivity. The underside of the ice acts like an upside-down coral reef, pro-
viding young krill both food and protective shelter. But heavy winter
sea ice that used to appear 4 out of 5 years declined in the 1990s to only
1 or 2 years out of 5. If the krill population declines along with the sea
ice that could wipe out populations not only of penguins, but also seals
and whales that depend on the krill for their survival. An average blue
whale consumes more than 4 tons of krill per day.
The Antarctic Peninsula has been making other kinds of climate
news of late as huge pieces of the Larson-B ice shelf—including one
berg twice the size of the state of Delaware—have begun calving off its
eastern shore.
Scientists are now discussing the possibility that the western
Antarctic ice sheet adjacent to the peninsula could experience a sudden
meltdown, raising global sea levels by 18 to 20 feet (instead of the 1 to
3 feet currently predicted by 2100). While most experts believe this
melting will occur sometime after the twenty-first century, by the time
they know for sure, it will be too late to do anything about it.
Other dramatic signs of climate change include retreating glaciers
and increased snowfall (warming in Antarctica means more precipita-
tion in the form of snow). There is also the displacement of ice-depend-
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