Ocean acidification was first recognised as an emergent threat to marine systems in 1999. Over the past two decades scientific understanding of the issue has grown exponentially and it is now well understood that changing ocean chemistry due to the absorption of anthropogenic carbon dioxide (CO2) emissions is likely to result in devastating consequences for marine biodiversity and the goods and services it provides. Collective action to address ocean acidification is needed at the international level, and while the international community has agreed through the Sustainable Development Goals to ‘minimize and address the impacts of ocean acidification’ (SDG 14.3), there is a lack of clarity as to how this should be best achieved or through which instrument.
No existing multilateral environmental agreement (MEA) explicitly requires a response to it and the issue remains largely unaddressed in international environmental law and policy. Moreover, ocean acidification intersects with several environmental and social issues already addressed by international treaties; including climate change, biodiversity conservation, marine environmental protection, sustainable development and economic prosperity. Ocean acidification is therefore an issue that is simultaneously of relevance to and falls between the mandates of a number of international environmental regimes, and has therefore been described as sitting ‘at a rather cracked interface between the climate, biodiversity and oceans regimes’.
The creation of a new unifying agreement for ocean acidification has been proposed as one way of managing this emergent problem. This, however, is arguably a superfluous, confusing and unrealistic option, largely due to the already congested nature of the existing MEA landscape. The creation of a new ocean acidification treaty would necessarily need to duplicate much of the existing governance architecture, including most importantly the elements that regulate CO2 emissions. Further, there is no discernible pressure for the creation of such a treaty from within the international policy community. Moreover, the creation of a new treaty is a time-consuming process that, assuming its success, can take decades to come to fruition. This timeframe is inconsistent with the urgent need to address ocean acidification. Thus, the development of a single unifying agreement for ocean acidification is unlikely. Addressing ocean acidification in the future will therefore require an enhanced effort under existing MEAs.
To date, ocean acidification has appeared in the resolutions, outcome documents or action plans of five global MEAs. The Parties to two of these conventions, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention and Protocol) and the Convention on Biological Diversity (CBD, 1992), have formally recognised ocean acidification as a threat and have initiated activities within their mandates to respond. Parties to the other three conventions, the Convention on the Conservation of Migratory Species of Wild Animals (CMS, 1979), the UNFCCC and the World Heritage Convention (WHC, 1972) have not recognised ocean acidification in any formal way or made efforts to explicitly include the issue within existing work. Rather, ocean acidification has been mentioned as a possible threat to particular areas or species of concern under the WHC and CMS respectively. Under the United Nations Framework Convention on Climate Change (UNFCCC, 1992), ocean acidification was included in a footnote in the Cancun Agreements that listed several types of slow-onset events, this is the only mention of ocean acidification in any decision or outcome document of the Conference of the Parties to the UNFCCC. This collection of regimes engaging with ocean acidification have been described as an emergent regime complex.
The UNFCCC, the primary international instrument for regulating CO2 emissions, is currently calibrated to address the thermal impacts of rising emissions, and efforts under this regime have largely overlooked ocean acidification. However, there has been increasing pressure from within civil society (including from research institutions, NGOs and international organisations, like IOC-UNESCO) to more effectively include ocean acidification considerations within the work of the UNFCCC. These efforts have increased the profile of ocean-issues within the climate regime, including the naming of COP-25 as the ‘blue COP’, with ocean-specific language included in the COP’s outcome documents and the creation of Ocean and Climate Change Dialogue and The Because the Ocean Initiative. The first of these initiatives provides a space for Parties and non-Party stakeholders to discuss how to strengthen and mitigation action on ocean and climate change. The second, focuses on the inclusion of the ocean into climate policy and strategies. There is a need for greater inclusion of ocean acidification across nationally directed commitments and adaptation plans, as well as work to combat slow onset events.
While individual MEAs have the potential to respond to ocean acidification, the interactions between regimes can enhance or detract from a coherent international response. Two regimes that could drive this process are the CBD and the United Nations Convention on the Law of the Sea (UNCLOS, 1982). These regimes are the principal treaties mandated to govern the use and protection of the marine environment and the conservation of marine biodiversity. Yet, these two conventions are limited in their ability to directly regulate global CO2 emissions and therefore mitigate future ocean acidification.
The CBD and UNCLOS, however, can (and have in the case of the CBD) act to manage the impacts of ocean acidification and work to create synergies between regimes with an interest in addressing ocean acidification. UNCLOS has been recognised as establishing a legal framework for the regulation of all activities taking place within the marine environment, including ocean acidification. It is possible that UNCLOS could provide a framework for action on ocean acidification, providing the general obligations for addressing rising ocean acidity. Similarly, the CBD, which acts as the focal point for biodiversity work within the biodiversity cluster and the wider UN system, could set an agenda for addressing ocean acidification within future biodiversity work. Windows of opportunity currently exist to further integrate ocean acidification across both of these regimes.
Under UNCLOS countries are currently negotiating a legally binding instrument for the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction. The fourth session of the Intergovernmental Conference on Marine Biodiversity of Areas Beyond National Jurisdiction is due to take place early 2022 (postponed from 2021 due to Covid-19). The current negotiating text includes five mentions of ocean acidification. Assuming these make it into the final agreement, this will be the first global treaty that explicitly mentions ocean acidification. This will hopefully allow for important action on ocean acidification, including its consideration in both the establishing of marine protected areas and environmental impacts assessment. It could also become a focal point for the sharing of technology and best practices in terms of adaptation planning. The inclusion of ocean acidification under the UNCLOS umbrella also suggests that there could be room for establishing a target or boundary for ocean acidification (much like the 1.5/2oC boundary for global temperature rise).
The concluding part of the 15th meeting of the CBD Conference of the Parties will be held in April 2022, at which it is intended that a post-2020 global biodiversity framework will be adopted. This framework will act as a steppingstone towards the CBD vision of a world ‘living in harmony with nature’. These types of strategic plans have been used by the biodiversity-related conventions as not only a key instrument to guide and enhance implementation, but also as vehicles for enhanced collaboration among conventions. Moreover, the setting of global goals can play an important orchestration role in governing complex issues across fragmented governance landscapes by bringing cohesion to collective actions. The post-2020 biodiversity framework can establish the importance of addressing the biodiversity-ocean acidification nexus, both in terms of the efforts needed for adaptation, but also in terms of biodiversity as a solution to ocean acidification. Integration of considerations of ocean acidification across the post-2020 biodiversity framework can assist in its diffusion across the biodiversity cluster. This may contribute to intensified action to respond to acidification both within individual regimes and through broadening partnerships and consolidation of synergies.
Enhancing work across the emergent ocean acidification regime complex will allow for a strengthening of synergies and a lessening of conflict between the participating regimes. Further, this work will allow for greater sharing of knowledge, best practices and the building of momentum to future combat ocean acidification.