Ocean fertilization, or the application of nutrients such as iron or nitrogen to marine surface waters, has been proposed as a strategy to reduce the amount of carbon dioxide in the atmosphere, thus mitigating anthropogenic climate change. The theory suggests that adding extra nutrients to certain regions of the ocean will stimulate phytoplankton growth, which absorbs additional carbon, and eventually lead to the transfer of carbon to the deep sea where it will be out of contact with the atmosphere and therefore no longer able to contribute to global climate change. Leaving aside the issue of whether ocean fertilization could actually be effective in removing carbon dioxide from the atmosphere for a substantial length of time, the proposal has met with various reactions. Scientists have largely been supportive of research aimed at understanding nutrient limitation in surface waters in regions such as the Southern Ocean and the Equatorial Pacific, the results of which have relevance for the applied question of deliberate fertilization. But many have spoken out against large-scale fertilization as an acceptable strategy for mitigating climate change, citing concerns about negative impacts to oceanic food webs and the inability to control impacts in a fluid medium. Nonetheless, small entrepreneurs and other entities have pursued the right to fertilize the ocean, suggesting that such efforts would not only have positive benefits for climate, but would also provide additional food in the way of fish stocks for impoverished coastal regions. Thus far, little is known about the effectiveness or the controllability of ocean fertilization. Governments such as the U.S. have not invested significant funds in researching the potential of ocean sequestration, preferring instead to focus instead on geologic sequestration and other methods for increasing carbon storage. The public remains largely unaware of ocean fertilization as an idea, although in cases where deep ocean injection has been proposed, there has often been vigorous local opposition, for example in Hawaii and Norway in 2002).

The standard arguments in favor of ocean fertilization as a technique to sequester carbon can be summarized as follows: 1) the threat of climate change is severe enough that we should pursue all possible avenues to mitigate it, including manipulating the ocean; 2) the ocean is vast, covering more than 70% of the globe, and should be considered a logical place to store excess carbon; 3) supplying extra nutrients to the surface may increase the harvestable biomass of fish and species important to human welfare; 4) nutrient addition merely mimics and amplifies natural processes; and 5) most excess carbon will eventually return to the ocean on its way to equilibration in the earth system, and thus ocean fertilization can be seen as simply accelerating that process (or, more simply, it can “buy us time”). By contrast, the standard arguments against ocean fertilization can be summarized as follows: 1) we cannot control the results of adding nutrients to the ocean, especially since it is a fluid medium; 2) adding nutrients to a food web will have unknown, negative impacts on the natural ecosystem; 3) it may not be effective at moving carbon to depth in the ocean for any length of time; 4) it does not remove carbon from the system permanently—carbon will eventually be equilibrated back to the atmosphere over millennia; 5) we should not use the ocean as a dump; and 6) ocean fertilization would be an engineering fix that does not address the core problem, i.e. emissions of carbon dioxide from burning fossil fuels.

Our question for this paper is whether it is permissible to change, modify, or sully an ambient (e.g. air or water-based) resource in order to clean up an environmental pollutant that sullies that same ambient resource (or that sullies an ambient resource with a similarly broad impact). More concretely, we wonder whether it is permissible to alter the marine environment through ocean fertilization in order to remediate the ocean or the atmosphere of carbon pollution. If so, we wonder how it could be permissible to introduce pollutants in some circumstances—as is the case when large-scale, ambient remediation technologies are introduced—but not to pollute in initial circumstances—as is the case when decentralized individual actors collectively create carbon pollution. If not, we wonder what accounts for the difference. We call this the Problem of Permissible Pollution. Our conclusion is that it is not permissible to change, modify, or sully an ambient resource in order to clean up an environmental pollutant to that same, or to an equivalent, ambient resource. The reason for this is that each individual actor is required to act according to a consistent principle with regard to their emissions. For this paper, we stipulate that what is wrong with individual-level pollution is that it is disrespectful of others. Because ocean fertilization will alter the ocean environment, and arguably the global environment, in a way that cannot be assented to by all, it commits the same wrong as individual-level emissions.

Our argument turns on a distinction between justified action and unjustified action, where the justification offered for an action is understood procedurally and deliberatively. In this case, we reason that individual or collective actors cannot, without globally expansive and multi-generational deliberative procedures, offer the justificatory support that would permit mammoth-scale ocean fertilization. Beyond the simple claim that such a justification is politically unfeasible, we suggest that it is also conceptually contradictory. Therefore, we argue that the wrong-making attribute of carbon emissions is not countered by the good-making attribute of remediation, and so the moral impermissibility of pollution stands.