It is Best to Avoid Prematurely Declaring Victory
Most geoengineering ideas involve identifying natural processes that remove CO2 from the atmosphere and then artificially enhancing them to accelerate the CO2 removal mechanism. One of the most widely boosted geoengineering concepts involves dumping iron into the ocean to encourage plankton growth.
This concept was championed by oceanographer John Martin who famously said, ""Give me a half a tanker of iron and I will give you another ice age".
The iron fertilization idea is based on the fact that large regions of the ocean have low iron contents, and lack of iron inhibits the growth of marine phytoplankton. Artificially adding iron to these regions should enhance phytoplankton growth, and phytoplankton shells incorporate CO2 from ocean water which ultimately is derived from atmospheric CO2. In theory the phytoplankton shells should then sink to the ocean bottom, sequestering the CO2.
This geoengineering idea has been extensively tested, perhaps more than any other geoengineering concept. At least nine scientific cruises have been made to various parts of the world's oceans, iron of various types and amounts has been added to the ocean, and phytoplankton growth was repeatedly observed to be enhanced.
At first the iron fertilization concept seemed to work so well that one almost expected to see the marine science vessels testing iron fertilization to come steaming back to port with giant "MISSION ACCOMPLISHED" banners streaming from the ships.
However, as with all geoengineering ideas, serious problems have arisen. In 2009 an attempt was made to measure how much carbon was actually being stored in ocean sediments as a result of iron fertilization. And the answer was ...... not very much.
UC Berkeley issued the following press release: :
Ocean Carbon: A Dent in the Iron Hypothesis
Plankton blooms do not send atmospheric carbon to the deep ocean
BERKELEY, CA – Oceanographers Jim Bishop and Todd Wood of the U.S. Department of Energy's Lawrence Berkeley National Laboratory have measured the fate of carbon particles originating in plankton blooms in the Southern Ocean, using data that deep-diving Carbon Explorer floats collected around the clock for well over a year. Their study reveals that most of the carbon from lush plankton blooms never reaches the deep ocean.
The surprising discovery deals a blow to the .... Iron Hypothesis, whose adherents believe global warming can be slowed or even reversed by fertilizing plankton with iron.
"Just adding iron to the ocean hasn't been demonstrated as a good plan for storing atmospheric carbon," says Bishop, a member of Berkeley Lab's Earth Sciences Division and a professor of Earth and planetary sciences at the University of California at Berkeley.
The iron fertilization idea is based on the fact that large regions of the ocean have low iron contents, and lack of iron inhibits the growth of marine phytoplankton. Artificially adding iron to these regions should enhance phytoplankton growth, and phytoplankton shells incorporate CO2 from ocean water which ultimately is derived from atmospheric CO2. In theory the phytoplankton shells should then sink to the ocean bottom, sequestering the CO2.
This geoengineering idea has been extensively tested, perhaps more than any other geoengineering concept. At least nine scientific cruises have been made to various parts of the world's oceans, iron of various types and amounts has been added to the ocean, and phytoplankton growth was repeatedly observed to be enhanced.
At first the iron fertilization concept seemed to work so well that one almost expected to see the marine science vessels testing iron fertilization to come steaming back to port with giant "MISSION ACCOMPLISHED" banners streaming from the ships.
However, as with all geoengineering ideas, serious problems have arisen. In 2009 an attempt was made to measure how much carbon was actually being stored in ocean sediments as a result of iron fertilization. And the answer was ...... not very much.
UC Berkeley issued the following press release: :
Ocean Carbon: A Dent in the Iron Hypothesis
Plankton blooms do not send atmospheric carbon to the deep ocean
BERKELEY, CA – Oceanographers Jim Bishop and Todd Wood of the U.S. Department of Energy's Lawrence Berkeley National Laboratory have measured the fate of carbon particles originating in plankton blooms in the Southern Ocean, using data that deep-diving Carbon Explorer floats collected around the clock for well over a year. Their study reveals that most of the carbon from lush plankton blooms never reaches the deep ocean.
The surprising discovery deals a blow to the .... Iron Hypothesis, whose adherents believe global warming can be slowed or even reversed by fertilizing plankton with iron.
"Just adding iron to the ocean hasn't been demonstrated as a good plan for storing atmospheric carbon," says Bishop, a member of Berkeley Lab's Earth Sciences Division and a professor of Earth and planetary sciences at the University of California at Berkeley.
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