January 2011: The Intergovernmental Oceanographic Commission (IOC) of the UN Educational, Scientific and Cultural Organization (UNESCO) has released a “Scientific Summary for Policymakers on Ocean Fertilization,” which considers the practicalities, opportunities and threats associated with large-scale ocean fertilization.

The publication, commissioned by the IOC of UNESCO and prepared with the assistance of the Surface Ocean Lower Atmosphere Study (SOLAS), summarizes activities and issues surrounding the use of ocean fertilization as deliberate interventions in the Earth’s climate system that might mitigate climate change. These activities are controversial, as illustrated by the fact that the Convention on Biological Diversity (CBD) decided in 2008 to ban all ocean fertilization activities in non-coastal waters until stronger scientific justification, assessed through a global regulatory mechanism.

This scientific summary provides an overview of the current scientific understanding of ocean fertilization with the aim to assist the regulatory framework through the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter and its Protocol (London Convention and London Protocol (LC/LP). In particular, the publication discusses the following issues: experimental, small-scale iron additions in high nutrient areas can greatly increase biomass of phytoplankton and bacteria, and the draw down of carbon dioxide in surface water; the impact of iron-based ocean fertilization on zooplankton, fish, and seafloor biota is unknown; large-scale fertilization could have unintended impacts such as increased risk of toxic algal blooms; the difficulty and cost to directly verify the total benefits and impacts of ocean fertilization; fertilization achieved through artificial upwelling is inherently less efficient for sequestration; and the essential role of monitoring to assess carbon sequestration and ecological impacts. [The Summary for Policymakers on Ocean Fertilization]