The Scientific and Policy Uncertainties Surrounding the Use of Ocean Fertilization to Transfer Atmospheric Carbon Dioxide to the Oceans
April 25, 2001 Washington D.C.
Carbon dioxide (CO2) is being emitted to the atmosphere in unprecedented amounts and the rate is accelerating. The control of this and other greenhouse gases must be made an international priority, and reducing anthropogenic emissions of CO2 is of primary importance. Additional mitigation measures may also be required, however, including carbon sequestration strategies. One of the strategies being considered involves adding iron, a plant nutrient, directly to surface seawater in key ocean areas to stimulate phytoplankton growth and use the ocean's 'biological pump' to deliver carbon to the deep sea. This procedure may have the potential to sequester atmospheric CO2 for centuries.
ASLO invited an international group of experts from academia, industry and government agencies to discuss the scientific and legal issues surrounding intentional fertilization of the ocean. These issues included the limits to our understanding of the ocean carbon cycle, the potential for stimulating ocean productivity, the environmental risks of ocean fertilization, and the appropriate intersection of science, government and industry in the pursuit of this possible CO2 mitigation option. Although the group was not unanimous on all issues, the workshop generated the following findings and recommendations:
FINDING 1. Re: Carbon dioxide sequestration by ocean fertilization
On the basis of available scientific information, we cannot dismiss ocean fertilization with iron as a mitigation option. However, computer models predict that it would at the very best reduce the expected increase of atmospheric CO2 by a small percentage(1). Achieving this degree of sequestration would entail major alterations of the ecosystem such as changes in food web structure and biogeochemical cycles as has been demonstrated in several research experiments to date. These changes will have unknown consequences, some of which will be inherently unpredictable.
There is commercial interest in small-scale fertilization
experiments to better understand the ocean carbon cycle and to take advantage
of anticipated carbon credits. Given the present state of knowledge and
technology, it is premature to justify carbon credits for ocean fertilization.
More fundamentally, there are profound deficiencies in our understanding of a broad range of ocean-atmosphere processes that must be addressed in order to assess the role of the oceans in climate regulation both through natural (via atmospheric mineral matter) and intentional iron enrichment.
FINDING 2. Re: Guidelines for the relationship among scientists, industry and government
Recognizing that the global ocean common requires special governance, and that both private and public resources will be used for carrying out the necessary scientific and policy research, partnerships should be created among academic scientists, industry, and government.
Examples for partnerships may come from the biomedical field, as well as other agreements governing the use of the sea.
FINDING 3. Re: Governance structure
No appropriate intergovernmental governance structure has been identified with specific authority for ocean fertilization, although many elements of existing treaties and conventions may be applicable to some portion of the ocean fertilization issue. International agreements on activities in the high seas have, for example, advanced the principles of a precautionary approach, the liability of polluters ("polluter pays"), transgenerational equity, and sharing knowledge and benefits.
Funding for the workshop came from: The Department of Energy, The National Science Foundation (NSF), The Office of Naval Research (Department of Defense) and The National Oceanic and Atmospheric Administration (NOAA).
1) These models assume
complete utilization of all available nitrogen and phosphorus in the fertilized
waters, thus this is a theoretical maximum based on many assumptions.