West Africa’s Rising Tide: Shaping the Future of Marine Geoengineering Governance

With climate change standing as a pressing emergency demanding immediate attention and comprehensive redress, marine geoengineering has emerged as a prospective avenue for mitigating anthropogenic greenhouse emissions. This article reviews the sketchy international governance seascape which has emerged to control the environmental risks posed by marine geoengineering with limited specific controls adopted under the London Convention and London Protocol (LC/LP) and the Convention on Biological Diversity. The article concludes by describing the foggy future for marine geoengineering governance. Many questions remain unanswered, such as next steps under the LC/LP, the climate change regime, and possibly through the United Nations Environment Assembly.

This article examines how climate change responses and marine environmental protection can be harmonized through the interplay of international judicial decisions—such as the Advisory Opinion of the International Tribunal for the Law of the Sea (ITLOS)—and the international legal frameworks represented by the United Nations Convention on the Law of the Sea (UNCLOS), the London Convention, and the London Protocol (LC/LP). Although marine-based technologies like Carbon Capture and Storage (CCS), marine geoengineering hold potential for greenhouse gas reduction, they also raise concerns regarding marine ecosystem disturbances and long-term environmental risks. By analyzing the ITLOS Advisory Opinion, this study highlights how UNCLOS-based obligations can be reaffirmed and operationalized through the reinforcement of due diligence, precautionary approaches, and international cooperation, as well as scientific grounding and enhanced monitoring requirements. The London Convention and Protocol, evolving from a dumping-control treaty to a comprehensive framework capable of addressing CCS and marine geoengineering, serve as implementing agreements of UNCLOS, integrating climate change mitigation and marine environmental objectives. The article concludes that expanding the ratification and acceptance of amendments to the London Protocol, strengthening scientific evidence, and promoting stakeholder participation can facilitate a more sustainable and integrated approach to marine governance in an era of climate change.

The London Convention and London Protocol are the two main international treaties of global application addressing the protection of the marine environment from pollution caused by the dumping of wastes and other matter into the sea. This article describes how the treaties were developed and adopted, explores their relationship with the overarching 1982 United Nations Convention on the Law of the Sea (LOSC) and examines how the treaties are administered to implement their vision of ‘two instruments, one family’. The article also highlights the ground-breaking steps the London Convention and London Protocol have taken to address new threats to the ocean, which include regulating new climate change mitigation technologies that have the potential to cause harm to the marine environment.

The State of the Science for Marine Carbon Dioxide Removal (mCDR) – A Summary for Policy MakersAuthors: Chris Vivian* (WG Co-Chair), Miranda Boettcher*, Philip Boyd (WG Co-Chair), Alejandro H. Buschmann, Long Cao, Olaf Corry, Mike Elliott, Aarti Gupta, Clare Heyward, Rahanna Juman, Alana Lancaster, Nadine Mengis, Christine Merk, Andreas Oschlies, Masahiro Sugiyama, Guanqiong Ye.Affiliation: Members of GESAMP Working Group 41 (www.gesamp.org/work/groups/41) *Corresponding authors: chris.vivian2@btinternet.com, miranda.boettcher@swp-berlin.orgIn 2019 GESAMP Working Group 41 published a report titled ‘High Level Review of Wide Range of Proposed Marine Geoengineering Techniques’ (GESAMP, 2019[1]). It reviewed 27 approaches (including variations of approaches) including Carbon Dioxide Removal (CDR), Albedo Modification (AM), and hybrid (i.e., for purposes extending beyond CDR or AM) technologies. The report was one of the first high-level assessments of ‘marine geoengineering’ interventions. The report highlighted that the assessment was not able to be fully comprehensive, and that there was a need to further “Foster the development of socio-economic, geopolitical and other relevant societal aspects of marine geoengineering assessments, including societally relevant metrics where possible, to ensure a holistic approach to subsequent assessment process(es)”.Since 2020, there has been a surge of interest in marine CDR (mCDR) techniques to store carbon in ocean reservoirs using a range of methods. However, all of these techniques are in the early stages of development with much still to learn about their potential efficacy, environmental impacts and societal implications. Most interest is currently focused on ocean alkalinity enhancement (which includes mineral, electrochemical and electrodialysis techniques), biomass sinking (e.g. crop wastes and macroalgae) into the deep ocean, direct ocean capture of CO2 and ocean iron fertilization (OIF), which pose many technical, environmental, political, legal and regulatory challenges, among others. This increased interest is reflected in the continuing significant increase in the number of scientific papers on mCDR, the growing number of start-ups developing mCDR techniques, the significant funding for mCDR research announced by the US and the EU in 2023 and the current consideration of potential regulation of several mCDR techniques by the London Protocol Parties. This has led to significant number of field trials/pilot studies taking place or being planned in the marine environment for a range of mCDR techniques.The paper will review the current state of the science for mCDR techniques with a focus on those techniques that are currently under active investigation. [1]http://www.gesamp.org/site/assets/files/1996/rs98e-1.pdf

Overall interest in marine geoengineering (MGE) techniques and in their potential to mitigate the effects of climate change, as well as the multiple interests driving urgency for deployment, have intensified. This article considers the scientific, measured, transparent, and robust approach taken by the joint-meetings of the Governing Bodies of the 1972 London Convention and the 1996 London Protocol and the regulatory framework they are developing in response, with a particular focus on the regulation and guidelines for legitimate scientific research for MGE activities. It unpacks key attributes of the research assessment framework, particularly its acknowledging and accounting for scientific gaps and uncertainties, as well as its informed application of the precautionary approach. This is especially relevant in the context of rapidly growing interest in MGE as a means of climate mitigation.

The Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, 1972 (London Convention) and its more modern, self-contained 1996 Protocol (London Protocol) aim to protect the Marine environment from all sources of pollution and, in particular, control and manage the dumping of wastes and other matter at sea. This 2021 edition of the Waste Assessment Guidelines under the London Convention and Protocol presents updated guidance to facilitate the implementation of the London Convention and London Protocol, including Revised specific guidelines for the assessment of vessels and Revised specific guidelines for assessment of platforms or other man-made structures at sea. It also provides a list of additional guidance documents developed by the Contracting Parties, to further assist new and prospective Parties in the implementation of the treaties.

In this chapter an overview is given of the existing international regulation of marine geo-engineering techniques. Two techniques—ocean fertilization and the sequestration of carbon dioxide in sub-seabed geological formations—have been either experimentally studied or even deployed, whereas all other forms of marine geo-engineering have remained in their early infancy. Both techniques could pose a significant risk to the environment. In 2008 Contracting Parties to both the London Convention and the London Protocol and the Parties to the Convention on Biological Diversity (CBD) adopted a non-binding moratorium on ocean fertilization activities with the exemption of small-scale research projects. In 2010 this non-binding moratorium was extended to all climate-engineering activities by Parties to the CBD. In 2013 a—legally binding—amendment to the London Protocol with regard to the regulation of marine geo-engineering activities was approved. The amendment could serve as a model for the regulation of other climate-engineering activities (e.g. solar radiation management in the stratosphere) in many respects.

The complex nexus between climate and ocean governance is increasingly being acknowledged. Not only is there growing awareness of the risks posed to marine environments by climate change (deoxygenation, acidification, coral bleaching, etc.), there is also an increasing focus on the role of the ocean in mitigating adverse effects of climate change. Proposals for intervening into marine environments to help mitigate climate change (either by increasing ocean carbon sequestration or albedo properties, sometimes collectively termed ‘marine geoengineering’) have proliferated in recent years. All of these proposals are in the early stage of development, and they present many environmental, technological, political and societal unknowns that are yet to be comprehensively researched and assessed. It is essential to adopt a broad and transdisciplinary approach to assessing ocean interventions for climate mitigation given the inherently dynamic and interconnected nature of marine ecosystems, the potential for conflicts with other marine activities and marine protection, as well as concerns about the possible effects on social and cultural relationships with the ocean.GESAMP is a group of independent experts that provides advice to the UN system on scientific aspects of marine environmental protection. In 2015, GESAMP established Working Group 41 on ‘marine geoengineering’ under the lead of International Maritime Organization (IMO) and supported by The Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO) and World Meteorological Organization (WMO). In 2019, GESAMP WG41 published a report which undertook one of the first high-level assessments of ‘marine geoengineering’ interventions. The report highlighted that the assessment was not able to be fully comprehensive, and that there was a need to further “[f]oster the development of socio-economic, geopolitical and other relevant societal aspects of marine geoengineering assessments, including societally relevant metrics where possible, to ensure a holistic approach to subsequent assessment process(es)” (GESAMP 2019). Building upon this recommendation, the Terms of Reference for the second phase of GESAMP WG 41 that began in 2020 state that one key task of the expanded group is to: ‘Develop a framework to integrate inputs from natural sciences and societal disciplines into a holistic assessment of ocean interventions for climate change mitigation or other purposes consistent with the London Protocol’s definition of marine geoengineering, to be used by regulators, policy-makers, funders or anyone considering or permitting proposals’.WG 41 has correspondingly developed a transdisciplinary Ocean Intervention Assessment Framework (OIAF) that is designed to help a wide variety of potential users (i.e. state regulators, policy-makers, developers, funders and other stakeholders involved in assessing and permitting proposals) to holistically assess relevant ecological, scientific, institutional and societal issues that may arise in relation to ocean intervention proposals.This presentation/paper presents and discusses the GESAMP OIAF by: (1) outlining and reflecting upon the process by which it was developed; (2) providing an illustrative example of how it could be applied to a specific ocean intervention proposal, and (3) showing how the application of the framework can help all those involved in future research, assessment, development and management of ocean interventions to embody the ethos of responsible research and innovation.

Notwithstanding adoption of the Paris Agreement on climate change, mitigation of greenhouse gas emissions appears unlikely to achieve the stated goal of limiting the mean global temperature increase to 2°C. Under many scenarios, achieving this goal would require not only vigorous mitigation efforts, but also the deployment of carbon dioxide removal (CDR) technologies or solar geoengineering. While serious consideration of solar geoengineering remains fraught with peril, the use of CDR to remove carbon dioxide from the atmosphere and store it elsewhere appears increasingly likely. CDR techniques generally would have to be undertaken on a massive scale to be effective. However, the techniques are not ready for deployment, and their widespread use would impact land use, biodiversity, food security, water availability, and other resources. The potential impacts of widespread CDR deployment demand greater attention to managing CDR efforts and their effects. The Paris Agreement does not directly mention CDR, however, and relatively little attention has been directed to CDR governance thus far. This Article explores key issues of CDR governance, such as promoting the generation of information, mainstreaming CDR into public and policy discussions, and furthering CDR development while avoiding lock-in of suboptimal technologies.

Marine carbon dioxide removal (mCDR) refers to the techniques and technologies designed to increase the amount of carbon dioxide the ocean already captures and stores naturally through ecological and physical processes. As such, the deployment of mCDR could contribute to achieving global climate goals. However, many uncertainties and unknowns still surround these technologies, particularly concerning their efficiency and potential impact on ecosystems and societies. Moreover, the governance framework of mCDR is fragmented and falls short in adequately regulating the approaches undergoing development. To assess the status of current knowledge on mCDR, analyse governance challenges, and provide recommendations for mCDR research and potential deployments, we reviewed scientific literature and organised a series of workshops involving researchers and civil society representatives. Our recommendations are discussed and summarised into three key points: (1) the need to prioritise decarbonisation over mCDR deployment and limit the potential negative social and ecological impacts associated with these techniques; (2) the importance for research, based on clear guidelines, to play a crucial role in guiding mCDR development, and in particular on monitoring, reporting, and verification; (3) the urgency to strengthen and harmonise the governance framework of mCDR, which should be done in a way inclusive of civil society, ensuring equity and participation in all decision-making processes. We propose that these findings should guide both research agendas—including the seventh Intergovernmental Panel on Climate Change’s Assessment Report cycle (AR7)—and multilateral processes, in particular the London Convention and Protocol, the Convention on Biological Diversity, the United Nations Framework Convention on Climate Change, the United Nations Convention on the Law of the Sea, and the High Seas Treaty (BBNJ).

Abstract. Solar radiation management (SRM) and carbon dioxide removal (CDR) are geoengineering methods that have been proposed to mitigate global warming in the event of insufficient greenhouse gas emission reductions. Here, we have studied temperature and precipitation responses to CDR and SRM with the Representative Concentration Pathway 4.5 (RCP4.5) scenario using the MPI-ESM and CESM Earth system models (ESMs). The SRM scenarios were designed to meet one of the two different long-term climate targets: to keep either global mean (1) surface temperature or (2) precipitation at the 2010–2020 level via stratospheric sulfur injections. Stratospheric sulfur fields were simulated beforehand with an aerosol–climate model, with the same aerosol radiative properties used in both ESMs. In the CDR scenario, atmospheric CO2 concentrations were reduced to keep the global mean temperature at approximately the 2010–2020 level. Results show that applying SRM to offset 21st century climate warming in the RCP4.5 scenario leads to a 1.42 % (MPI-ESM) or 0.73 % (CESM) reduction in global mean precipitation, whereas CDR increases global precipitation by 0.5 % in both ESMs for 2080–2100 relative to 2010–2020. In all cases, the simulated global mean precipitation change can be represented as the sum of a slow temperature-dependent component and a fast temperature-independent component, which are quantified by a regression method. Based on this component analysis, the fast temperature-independent component of the changed atmospheric CO2 concentration explains the global mean precipitation change in both SRM and CDR scenarios. Based on the SRM simulations, a total of 163–199 Tg S (CESM) or 292–318 Tg S (MPI-ESM) of injected sulfur from 2020 to 2100 was required to offset global mean warming based on the RCP4.5 scenario. To prevent a global mean precipitation increase, only 95–114 Tg S was needed, and this was also enough to prevent global mean climate warming from exceeding 2∘ above preindustrial temperatures. The distinct effects of SRM in the two ESM simulations mainly reflected differing shortwave absorption responses to water vapour. Results also showed relatively large differences in the individual (fast versus slow) precipitation components between ESMs.

The London Convention (LC), adopted in 1972, and its successor, the London Protocol (LP) of 1996, constitute key regulatory frameworks working in parallel, aimed at mitigating waste dumping at sea and safeguarding the marine environment. These treaties, which share the objective of controlling marine pollution, have also evolved to address emerging environmental issues such as marine geoengineering and carbon capture and storage within the context of the current triple planetary crisis. As the LC/LP regime marked its fiftieth anniversary in 2022, both achievements and ongoing challenges in combating pollution from dumping activities were acknowledged, emphasising the need for continual adaptation to protect the marine environment effectively. This article examines the adaptability and impact of the LC/LP regime over the past five decades, identifying strengths and proposing future steps to ensure the preservation of ocean health for future generations.

Geoengineering options such as negative emissions technologies (NETs) or greenhouse gas removal (GGR) may need to contribute towards decarbonization, by removing CO2 from the atmosphere and storing it safely in biological or geological sinks, or reflecting sunlight back into space via solar radiation management (SRM). Despite concerns about them, GGR and SRM are increasingly discussed as crucial complements to traditional climate change mitigation. Others routinely dismiss both SRM and GGR methods as a distraction from mitigation, or even as a potential moral hazard that induces complacency in reducing emissions. Yet, if climate impacts turn out to be more sudden and severe than currently known, such strategies could provide a rapid backstop to implement deeper emissions reductions, especially with techniques that require time to scale-up. Despite their importance and controversial status, most research on GGR and SRM remains technical, rather than social, and that knowledge of their technical characteristics remains limited, even within the physical and engineering sciences. Moreover, existing GGR and SRM options are changing rapidly in terms of their technical design, cost, and performance, and therefore scalability and deployment potential. To contribute to the debate, this study reviews and summarizes a large number of geoengineering assessments published over the past decade to document prospective benefits, but also reveal potential risks. It aims to provide a comprehensive evidence base on GGR and SRM technologies that is rigorous, timely, and interdisciplinary. This article begins by briefly defining geoengineering and associated technologies, describing how various techniques work, and summarizing recent market trends up until early 2021. Then, it discusses a series of advantages and disadvantages to these options before identifying tensions, research gaps, and a critical research agenda. It concludes with implications for research, policy, and governance.

<p>Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR) have been proposed to mitigate global warming in the event of insufficient greenhouse gas emission reductions. We have studied temperature and precipitation responses to CDR and SRM with the RCP4.5 scenario using the MPI-ESM and CESM Earth System Models (ESMs). The two SRM scenarios were designed to meet different climate targets to keep either global mean 1) surface temperature or 2) precipitation at the 2010-2020 level via stratospheric sulfur injections. This was done in two-fold method, where global aerosol fields were first simulated with aerosol-climate model ECHAM-HAMMOZ, which were then used as prescribed fields in ESM simulations. In the CDR scenario the annual CO<sub>2</sub> increase based on RCP4.5 was counteracted by a 1% annual removal of the atmospheric CO<sub>2</sub> concentration which decreased the global mean temperature back to the 2010-2020 level at the end of this century. </p><p>Results showed that applying SRM to offset 21st century climate warming in the RCP4.5 scenario led to a 1.42%  (MPI-ESM) or 0.73% (CESM) reduction in global mean precipitation, whereas CDR increased global precipitation by 0.5% in both ESMs for 2080-2100 relative to 2010-2020. To study this further we separated global precipitation responses to a temperature-dependent and a fast temperature-independent components. These were quantified by a regression method. In this method the climate variable (e.g. precipitation) is regressed against the temperature change due to the instantaneous forcing. Temperature-dependent slow response and temperature independent fast response are given by the fitted regression line. We showed that in all simulated geoengineering scenarios, the simulated global mean precipitation change can be represented as the sum of these response components. This component analysis shows that the fast temperature-independent component of atmospheric CO<sub>2</sub> concentration explains the global mean precipitation change in both SRM and CDR scenarios. Results showed relatively large differences in the individual precipitation components between two ESMs. This component analysis method can be generalized to evaluate and analyze precipitation, or other climate responses, basically in any emission scenario and in any ESM in a conceptually easy way. </p><p>Based on the SRM simulations, a total of or 292-318 Tg(S) (MPI-ESM) or 163-199 Tg(S) (CESM) of injected sulfur from 2020 to 2100 was required to offset global mean warming based on the RCP4.5 scenario. The distinct effects of SRM in the two ESM simulations mainly reflected differing shortwave absorption responses to water vapor. To prevent a global mean precipitation increase, only 95-114 Tg(S) was needed. Simultaneously this prevent the global mean climate warming from exceeding 2 degrees above preindustrial temperatures in both models. </p>

We introduce solar geoengineering (SG) and carbon dioxide removal (CDR) into an integrated assessment model to analyze the trade-offs between mitigation, SG, and CDR. We propose a novel empirical parameterization of SG that disentangles its efficacy, calibrated with climate model results, from its direct impacts. We use a simple parameterization of CDR that decouples it from the scale of baseline emissions. We find that (a) SG optimally delays mitigation and lowers the use of CDR, which is distinct from moral hazard; (b) SG is deployed prior to CDR while CDR drives the phasing out of SG in the far future; (c) SG deployment in the short term is relatively independent of discounting and of the long-term trade-off between SG and CDR over time; (d) small amounts of SG sharply reduce the cost of meeting a [Formula: see text]C target and the costs of climate change, even with a conservative calibration for the efficacy of SG.