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To save Antarctica from following the fate of the (doomed) Arctic ice cap, we must place our faith in phytoplankton, says Victor Shahed Smetacek. Though it may already be too late to save the Arctic -- as we've written before, most scientists predict it will be gone by century's end -- it is possible that we could forestall the wholesale melting of the Antarctic ice cap if we start dumping large amounts of iron into the Southern Ocean.
If you're a longtime reader of this site, then iron fertilization won't be anything new to you (in fact, we first described Smetacek's plan a year ago): The basic gist is that, by fertilizing large patches of the ocean with iron filings (typically as iron sulfate particles), you kickstart phytoplankton productivity by allowing them to increase their rates of photosynthesis -- which leads to more atmospheric carbon dioxide being taken up in the ocean. Smetacek, an oceanographer from the University of Bremen whose research I've been closely following over the last few years, happens to be one of iron fertilization's most vocal proponents (and an excellent scientist). The best way to naturally sequester carbon, he believes, is to use phytoplankton to suck up excess carbon dioxide and drag it to the bottom of the ocean when they die, ensuring the gas doesn't get released back to the atmosphere. In an interview with the New Brunswick Business Journal, he said that iron-enriched phytoplankton could remove up to a gigaton, or one trillion kilograms (!), of carbon dioxide every year.
Derwin Gowan describes his plan in more detail:
However, it would take only five to 10 ocean-going ships, possibly tankers or ore carriers, to fertilize the oceans each year with iron sulphate, a waste product from smelting titanium and iron, he said.
The ships would drift with wind and current. They might accommodate tourists, maybe summer students, who would underwrite part of the cost. They might even lend their labour to shovel the stuff overboard.
The project would cost in the hundreds of millions of dollars, rather than the billions or trillions it would costs for other geo-engineering proposals - such as seeding the upper atmosphere with particles to reflect sunlight back into space, Smetacek said. It could save hundrds of millions of people from being displaced, he said.
His plan certainly won't please the many environmentalists and scientists who are (understandably) wary of tinkering with the planet on such a grand scale. (As someone who's heard/learned a lot about iron biogeochemistry and oceanography over the last year and a half, I have to say that I'm still not fully convinced of OIF's merits.)
Some also argue that using geoengineering -- other techniques include carbon capture and sequestration (CCS) and injecting sulfate aerosols into the stratosphere -- will give big industries carte blanche to keep on polluting, reducing the effectiveness of GHG mitigation and energy conservation efforts.
Recognizing this, Smetacek acknowledges that any large-scale iron fertilization demonstration will need to be paired with stringent emission caps and mitigation efforts to have a sustained impact on climate change. Also, he doesn't believe that companies should be allowed to engage in iron fertilization, because he argues that all aspects of fertilization need be tightly controlled and overseen by trained scientists.
He envisages a long-term fertilization program that would remove 100 to 1,000 megatons of carbon every year. It remains to be seen whether his lofty scenario will square with reality, however, since there isn't yet any empirical evidence to back up his projections.