Questions and controversy continue to swirl around what has been characterized as a rogue geoengineering experiment in international waters off the coast of British Columbia. But whether the action was legal under international law or likely to be effective from a scientific perspective are beginning to become clearer.
Last week, The Guardian newspaper first reported that in July, a retrofitted fishing trawler dispersed 100 tons of iron dust in an ocean eddy about 321 kilometers west of the islands of Haida Gwaii. The iron was intended to foster the growth of phytoplankton and thereby boost the entire marine food chain which it supports, including salmon valued by the indigenous Haida people who live in the area. Such "fertilization" projects have also been touted as a way to soak up atmospheric carbon dioxide and curb global warming.
At this point, answers to the legal questions surrounding the fertilization experiment seem the most clear. The experiment was conducted by the Haida Salmon Restoration Corp., and backed by a California businessman, Russ George. The ETC Group, an environmental watchdog organization, contends that the iron-fertilization scheme was a violation of international law, including the U.N. Convention on Biological Diversity (CBD) and the London convention on dumping of waste at sea, also known as the London Protocol. CBD did adopt two positions discouraging ocean fertilization, notes Edward Parson, a professor of law at the University of California, Los Angeles, School of Law. But these decisions are strictly advisory, and not legally binding, he adds. And while the London Protocol is binding, it only applies to the release of material intended to be dumped as waste, not released as part of a scientific experiment. Even if the quality of the science is dubious, as many ocean experts argue in this case, Parson says because the material was not dumped as waste, "there is no violation under international treaty." Canadian officials, however, are still investigating whether the experiment may have violated Canadian law.
As for the effectiveness of ocean fertilization, that seems less clear. Satellite images taken before and after the iron release seem to show a marked increase in phytoplankton. However, Kenneth Denman, an oceanographer with the University of Victoria in Canada, argues that it's impossible to conclude whether this plankton bloom was due to the added iron. The Haida eddies, where the iron was released, is a natural ocean circulation pattern that carries iron-rich coastal waters as far as 1000 kilometers off shore. The eddies trigger natural plankton blooms each summer, which could account for most if not all of what is showing up in the satellite images. "It's possible what they show is from the natural iron," Denman says. He adds that it will likely be impossible to ever produce useful science from the test, because it appears that the experimenters did not set up careful control studies to compare fertilized waters with waters from previous years, as well as unfertilized regions.
Even if the iron release caused this summer's phytoplankton bloom, it's still difficult to determine what impact this will have. The proponents of the test have said that they carried it out to promote increases in salmon stocks as well as fight climate change by sequestering atmospheric carbon. Some recent evidence does suggest that added iron can boost fish stocks, Denman says. In 2008, a volcano in Alaska's Aleutian Islands erupted, spewing iron-rich ash throughout the North Pacific. Phytoplankton blooms followed and salmon runs spiked to century-high levels in 2010. But Denman argues that there's not enough data to conclude that iron fertilization from the eruption caused the fish population boom. "People are assuming there is a link. But basically it's conjecture and speculation," Denman says.
That said, a dozen smaller-scale iron-fertilization experiments do show that adding iron to otherwise nutrient-rich ocean waters can trigger phytoplankton blooms. But studies to date suggest that ocean fertilization is a relatively inefficient way to sequester large amounts of carbon from the atmosphere, says Phillip Williamson, an oceanographer and project manager at the Natural Environment Research Council and the University of East Anglia in Norwich, U.K., who just led a review of ocean fertilization experiments. According to that study, which appeared online on 12 October in Process Safety and Environmental Protection, if widespread ocean fertilization were practiced over the course of this entire century it could be expected to remove 25 gigatons to 75 gigatons of carbon from the atmosphere. That's less than 10% of the 900 to 2000 gigatons of carbon that humans are expected to add to the atmosphere over the same period. As the world struggles to limit atmospheric carbon, that may eventually seem a worthwhile effort. But aside from the cost of distributing all that iron, widespread iron fertilization would be expected to cause major changes in the ocean ecosystems where it was practiced.