But all that is child’s play compared with tracking carbon in a moving, shifting ocean. “You know there’s a forest there. It doesn’t move, and it doesn’t cross boundaries. But when you’re dumping iron in the ocean, you’re crossing national boundaries and potentially producing changes in other people’s ecosystems,” notes Anand Gnanadesikan, an oceanographer at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory, in Princeton, N.J.

In a press release, Planktos announced that its research vessel, the Weatherbird II, entered international waters in early November, sailing along a secret route to an undisclosed destination in the equatorial Pacific. It’s open knowledge, however, that Planktos has had its eye on a patch of water off the Galápagos Islands as a test site for a large-scale fertilization. (The company did not respond to requests for an interview.)

What The Experts Say

The firm contends that the amount of plankton has dwindled and that the offsets will restore it, a claim that some ocean scientists take issue with. “It shouldn’t be sold as a solution to a problem, when there isn’t any agreement that the problem exists,” says Ken Buesseler, a senior scientist at Woods Hole Oceanographic Institution, in Massachusetts.

Buesseler notes that carbon offsets are basically unregulated, which has made it relatively easy for environmental entrepreneurs to take advantage of a lax legal framework. Several organizations have suggested that standards are needed to fill the regulatory void and to serve as checks on carbon-­offset providers. Without the support of scientists—and those contacted for this ­article did not know of any experienced ocean scientists with a high-level affilia­tion with the company—Planktos’s ­offsets are unlikely to gain much popu­larity. According to Andy Dvoracek, a senior client manager at Dublin-based Ecosecurities Group, a company that helps other businesses reduce and trade their emissions, very few methodologies for carbon-sequestration projects have been approved in protocols such as the Voluntary Carbon Standards, developed in part by the International Emissions Trading Association, in Geneva. So far, none exist for iron fertilization. “Sequestration-type projects are a very controversial space,” Dvoracek says.

So much so, that even the ocean­ographers themselves can be chary. To attend a conference on iron fertilization at Woods Hole in late September, Archer decided to fly in from Chicago guilt-free. “I told people that I’d bought offsets for my plane tickets to go there, and everyone sort of laughed at me,” Archer says. “If iron fertilization becomes commercial before it’s proven to work, it’ll poison the whole notion of carbon offsets.”