The Guardian has a fascinating story today about Russ George, a California businessman who has been seeding the Pacific Ocean with iron in order to trigger a 3,800-square-mile plankton bloom. The idea has some promise as a geoengineering scheme to mitigate global warming—in theory, the plankton can suck carbon-dioxide out of the air and bury it down in the deep ocean when they die.

Yellow and brown colors show relatively high concentrations of chlorophyll in August 2012, after iron sulphate was dumped into the Pacific Ocean as part of a controversial geoengineering scheme. Photograph: Giovanni/Goddard Earth Sciences Data and Information Services Center/NASA

The only problem? George appears to be carrying out this scheme on his own, apparently without permission:

George says his team of unidentified scientists has been monitoring the results of the biggest ever geoengineering experiment with equipment loaned from U.S. agencies like NASA and the National Ocean and Atmospheric Administration. He told the Guardian that it is the "most substantial ocean restoration project in history," and has collected a "greater density and depth of scientific data than ever before".

"We've gathered data targeting all the possible fears that have been raised [about ocean fertilization]," George said. "And the news is good news, all around, for the planet." ...

International legal experts say George's project has contravened the UN's convention on biological diversity (CBD) and London convention on the dumping of wastes at sea, which both prohibit for-profit ocean fertilization activities.

As zany geoengineering schemes to slow global warming go, lacing the ocean with iron isn't a terrible one. Back in July, a research group at Germany's Alfred Wegener Institute for Polar and Marine Research found that the technique has potential to bury carbon in the deep ocean. Ken Caldeira of the Carnegie Institution estimates that large-scale iron-seeding could help the world sequester around 1 percent of its emissions. That's not nothing.

But scientists still worry about the consequences of artificially mucking with ocean ecology. In 2009, an op-ed in Nature by four researchers warned about possible unexpected side effects from large-scale iron fertilization — for instance, the dead plankton could pull key nutrients out of the ecosystem. Victor Smetacek, a researcher at the Alfred Wegener Institute, has said he doesn’t favor large-scale fertilization without further testing.

That's why George's experiment has some people alarmed. And it highlights one of the more subtle risks of geoengineering. Many of the ideas on offer to cool the planet are remarkably cheap. A single nation can't cut the world's carbon emissions on its own. But a single businessman can start seeding the world's oceans with iron. Someday, individual nations or even concerned environmental groups might be able to spend a couple million dollars to spray sulfates into the air to cool down the planet. 

The consequences of artificially altering the climate would be hard to predict, but if the techniques are cheap enough, rogue geoengineering will remain a distinct possibility.

Further reading:

--A primer on geoengineering, the techniques, the possible unintended consequences.

--A closer look at the science behind lacing the ocean with iron in order to create plankton blooms.

--Scientists have also found that it's possible for cities to block heat waves with artificial volcanoes. But the side effects could be worrisome.