Are we taking too big a risk?

A few more facts about the iron fertilization idea. Why am I talking about this now? It’s not new, but the increasing concern about the urgency of combatting climate change and the fact that this large-scale experiment is underway in nature, with as yet unresearched possible consequences, make this a good time to take a closer look.
First a bit more background:
Scientists believe “fertilizing” the ocean surface with trace amounts of iron will lead to blooms of phytoplankton, which soak up carbon dioxide in the marine plants. When the phytoplankton die, they sink to the depths of the ocean, with the carbon safely “locked” inside their cells, potentially storing it for decades or centuries in sediments on the ocean floor.
The trouble is we don’t know exactly how much carbon can be captured and stored this way, for how long, or, more crucially, what it means for the ecosystems of the ocean. This is being referred to as “geo-engineering” and sometimes seems to be taking us into the realms of science fiction stories. What does it mean for the species in the ocean, ocean acidity or the level of oxygen in the water?
Some scientists even fear it could lead to the release of nitrous oxide, another powerful greenhouse gas.
Interest in ocean fertilization is not driven by purely scientific or altruistic considerations. There is a commercial interest. Private companies have been working on the idea, because carbon credits can be sold.
It’s interesting that there is not a lot of big media coverage of it. The British Mail on Sunday did have a full page on it earlier this month. It outlines the questions – how much algae will sink to the bottom of the ocean, “safely” trapping Co2, and how long will it stay there? It also draws attention to the findings of a British scientist team that tiny particles of iron are released naturally into the sea, in the Southern Ocean, when icebergs melt. This proof that iron is occurring naturally in the region is, according to the paper, what led to the UN giving permission to move ahead with the experiment.
“Will green algae save the world from global warming?”
Nevertheless, the planned experiment is relatively large in scale and expected to produce a green algae bloom visible from space. Sceptical scientists say the negative effects may not become obvious until it’s too late to do anything about it.
More background on the Treehugger website