15-20 Times Less Carbon Sequestered by Ocean Iron Fertilization Than Some Estimates Claim: New Report

polarstern research ship photo

Germany recently dropped objections to a new ocean iron fertilization experiment. Photo Alfred Wegener Institut

New info on the effectiveness of geoengineering projects seems to be coming from all sides these days. The latest comes from Nature and reports on the 2004-2005 so-called CROZEX experiment, which observed the impact of natural iron fertilization on algal growth and carbon export in the Crozet Islands, 2000 km southeast of South Africa. The original article has the details on the experiment, but here's the part which prompted Nature to title their piece "Ocean fertilization: dead in the water?":Artificial Algae Bloom Not As Effective As Natural

The amount of carbon sequestered to 200 metres depth, while 18 times greater than that during an artificially induced bloom [...], was a stunning 77 times smaller than the amount that had previously been determined during a natural bloom in the nearby Kerguelen region. What's more, carbon flux at 3,000 metres, where carbon dioxide sucked up at the surface would be safely locked away for centuries, was just 3% of that at 100 metres. (Thomson Reuters Carbon Community)

According to the paper authors, "CROZEX carbon sequestration for a given iron supply...falls 15-20 times short of some geoengineering estimates." Which therefore has "significant implications for proposals to mitigate the effects of climate change through purposeful addition of iron to the ocean."

Read the full article (subscription required): Southern Ocean deep-water carbon export enhanced by natural iron fertilization

via: Nature, Thomson Reuters Carbon Community
German Government Green Lights Ocean Iron Fertilization Test After Review
Geoengineering to Stop Climate Change: The Effective, the Risky and the Useless Outlined in New Research Paper
Geo-Engineering Risk Potential Not An Excuse for Inaction, Scientist Says
Royal Society Launches Large-Scale Review of Geoengineering Proposals

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