Summary/Abstract
International ocean law governance is comprised of a patchwork of global framework agreements, sectoral agreements and customary international law rules that have developed over time in response to disparate issues. These include maritime access, fisheries management, shipping pollution, ocean dumping and marine scientific research (MSR). This patchwork of oceans governance contains several bodies of rules that might apply in governing marine geoengineering activities. However, these bodies of rules were negotiated for different purposes, and not specifically for the governance of marine geoengineering. The extent to which this patchwork of rules might contribute to marine geoengineering governance will vary, depending on the purpose of an activity, where it is conducted, which state is responsible for it and the types of impacts it is likely to have. Applying this patchwork to a specific marine geoengineering activity is complex, and existing rules may provide only limited concrete guidance as to how an activity ought to be conducted. The 2013 amendment to the London Protocol on ocean dumping provides the most developed and specific framework for marine geoengineering governance to date. But the capacity of this amendment to bolster the capacity of international law to govern marine geoengineering activities is limited by some significant shortcomings. Negotiations are under way to establish a new global treaty on conservation of marine biodiversity in areas beyond national jurisdiction, including new rules for area-based management, environmental impact assessments (EIAs) and capacity building/technology transfer. The potential provisions of this agreement could be pertinent to marine geoengineering options. This negotiation is both an opportunity and a risk for marine geoengineering governance. A new agreement has the potential to fill key gaps in the existing patchwork of international law for marine geoengineering activities in high-seas areas. However, it is also important that this new treaty be structured in a way that is not overly restrictive, which might hinder responsible research and development of marine geoengineering in high-seas areas.