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UMaine Oceanographer, Colleagues Say Selling Carbon Credits Premature in Unproven CO2-Reduction Plan

Contact: Fei Chai, (207) 581-4317
Tom Weber, (207) 581-3777

ORONO — A University of Maine oceanographer has joined several scientists from around the world in questioning the sale of carbon credits for a proposed CO2-reduction strategy until more is known about its possible long-term affects on the marine environment.

The method involves seeding large sections of the ocean with tanker loads of iron particles that mix with seawater to stimulate the growth of microscopic plants called phytoplankton. The atmospheric carbon dioxide that is absorbed by the plant blooms during photosynthesis, the theory goes, would be converted into organic material that would then be carried down into the deep ocean as the phytoplankton dies and sinks.

Carbon dioxide is among several “greenhouse gases” that are believed to contribute to global warming.  

Writing in the Jan. 11 Forum page of the journal Science, Fei Chai, an associate professor of oceanography in the School of Marine Sciences, and 14 colleagues argue that the process known as ocean iron fertilization (OIF) has not been studied sufficiently to determine how effective it really is in removing carbon, how long the carbon is retained in the deep sea, and whether it has the potential to harm marine life in the future.

Without that critical information, they say, it is premature to issue carbon credits to commercial OIF companies, which stand to earn profits by measuring how much carbon they remove and then selling the equivalent to companies that are required to offset the emissions they release into the atmosphere.

“Our paper makes a simple hard statement,” says Chai, who is also a cooperating associate professor of UMaine’s Climate Change Institute. “You shouldn’t sell carbon credits until you know how much carbon is being stored, and what are the potential negative impacts on the marine ecosystems.”

The international oceanographic community has done several small-scale studies of iron fertilization since 1993. And while the the experiments “greatly improved our understanding of the role of iron in regulating ocean ecosystems,” the scientists write, “they were not designed to characterize OIF as a carbon mitigation strategy.”

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