Arctic melt soaks
up carbon dioxide
- 08 January 2007
- From New Scientist Print
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The clouds of global warming don't exactly boast a silver lining, but there
is a little bonus. Melting sea ice in the Arctic
is enabling ocean waters to soak up more carbon dioxide from the atmosphere.
Ice retreat over the last 30 years has tripled the amount of CO2 the
Arctic Ocean can absorb.
Nick Bates of the Bermuda Institute of Ocean Sciences and colleagues
calculated CO2 uptake in the Arctic Ocean from measurements taken
from the Chuckchi Sea and Canada basin in 2002 and 2004. They
found that CO2 uptake from the atmosphere increased dramatically
during the summer months, when sea ice was at a minimum (Geophysical
Research Letters, DOI: 10.1029/2006GL027028).
"Sea ice acts as a barrier to gas exchange," says Bates. Overall
they calculated that the entire Arctic Ocean
is currently able to absorb up to 66 million tonnes of CO2 per year.
Future ice-melt may increase absorption by a further 20 million tonnes per
decade. However, this won't be enough to offset global warming: currently worldwide
emissions amount to over 30 billion tonnes per year.
From issue 2585 of New Scientist magazine, 08 January 2007,
page 16