So remember the scientists who wanted to put giant one-way tubes in the ocean in order to grow phytoplankton to suck up CO2? Apparently there are not one, but two private companies looking to do pretty much the same thing, only with iron filings instead of tubes. Vast areas of the ocean (see above - the places with not-blue color) have plenty of nitrogen and phospheros but are limited in plant growth because of lack of iron.

As I wrote previously, the benefits of iron fertilization are far from clear. There is evidence than iron fertilization could encourage the growth of undesirable (often poisonous) plankton, make the global warming worse, totally alter the local food chain - and oh yeah, it could do all this without actually making a dent in atmospheric carbon.

As first posted by Rick MacPherson, the private companies have responded to these concerns in different ways. The first, Climos, has proposed an ethics code for ocean carbon experiments. Well, that’s a good start, but still doesn’t convince me that this will work without serious deleterious effects. The second, Planktos, has a very snippy “Response to Current Controversies.” Planktos dismisses concerns over iron fertilization in a peremptory fashion, without providing citations. I’m not an expert in this field by any means, but I can certainly cite many papers that call Planktos’ claims of safety & efficacy into doubt.

I certainly hope that there will be a lot more small- to medium-scale experimentation before somebody goes and dumps a tanker of iron filings into the Southern Ocean. And I’m not exactly rushing to buy stock in these companies, either. But hey, if they’re right - I’ll be the first to celebrate.