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Carbon dioxide is the primary perpetrator of
climate change and most efforts to slow global warming go into
preventing CO2 production and aiding CO2 absorption. But a new study
suggests that the more CO2 we make, the more nature absorbs. So do we
really need all those rainforests?
Many scientists now look to carbon capture-and-storage technology as
a way to ward off the worst effects of climate change. With its help,
CO2 can be captured before it reaches the atmosphere - at a coal-fired
power station, for example. The gases can then be stored in depleted
natural gas reservoirs or in porous, subterranean rock. They can be
locked away for thousands of years deep under the Earth's surface,
sparing the atmosphere.
While this ingenious sounding technology is a popular subject for
discussion, the fact that nature has already mastered that exact task
is often forgotten: Plants, soil and the oceans - so-called "carbon
sinks" - all excel at absorbing greenhouse gases. "Almost 60 percent
of our emissions are stored in the oceans or in the ground," Susan
Trumbore of the Max Planck Institute for Biogeochemistry in Jena,
Germany, told Spiegel Online.
Many have long thought that these natural carbon sinks would at some
point stop absorbing CO2 because, among other reasons, warmer ocean
waters are unable to absorb as much CO2 as cooler waters. In addition,
thawing Arctic permafrost threatens to release the greenhouse gases
currently trapped there. Numerous studies between 1996 and 2006 have
indicated that the efficiency of carbon sinks has been reduced world
wide. But now, a newly published study indicates that the ecosystem can
absorb more of humanity's sins against the climate than previously
thought.
In a paper published in the journal Geophysical Research Letters,
Wolfgang Knorr, a German scientist at the University of Bristol, writes
that the percentage of man-made CO2 emissions reaching the atmosphere
has more or less remained constant for the last 150 years. Even as the
total amount of CO2 being pumped into the atmosphere has risen
dramatically, the amount that is trapped in the atmosphere has remained
at a steady 40 percent.
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