Navigating Potential Hype and Opportunity in Governing Marine Carbon Removal

Is Blue the New Green?

Marine environments are the blue frontier of a strategy for novel carbon sinks in post-Paris climate governance, from “nature-based” ecosystem management to industrial-scale technological interventions in the Earth system (Figure 1). Marine carbon dioxide removal (mCDR) approaches are diverse (Royal Society/Royal Academy of Engineering (RS/RAE), 2018; GESAMP, 2019)—although several resemble key terrestrial CDR (tCDR) proposals. Ocean alkalinisation (adding silicate mineral such as olivine to coastal seawater, to increase CO₂ uptake through chemical reactions) is enhanced weathering, “blue carbon” (enhancing natural biological CO₂ drawdown from coastal vegetation) is marine reforestation, and cultivation of marine biomass (i.e., seaweed) for coupling with consequent carbon capture and storage (CCS) is the marine variant of bioenergy and CCS (BECCS).

FIGURE 1

Figure 1. An overview of proposed marine carbon dioxide removal (mCDR) options, artwork © Rita Erven/GEOMAR.

Wetlands, coasts, and the open ocean are being conceived of and developed as managed carbon removal-and-storage sites, with practices expanded from the use of soils and forests. In this article, we explore increasing overall attention to marine environments and mCDR projects, and how this could manifest in four entwined knowledge systems and governance sectors: modeling pathways (in Intergovernmental Panel on Climate Change reports), climate policy and politics (the Paris Agreement and Net Zero commitments), innovation, and international legal frameworks. We compare growing interest in mCDR with that surrounding BECCS—an imperfect proxy for tCDR—as a springboard for thinking about mCDR's knowledge and innovation economy, potentials, and governance of research and development.

Why does BECCS matter? BECCS, and through it, the prospect of large-scale tCDR, emerged at the confluence of key trends in climate assessment and governance: it is an immature technological system that allows ambitious temperature targets to be reached in IPCC mitigation pathways, while reflecting rationales for “buying time” in climate policy and industry (Low and Boettcher, 2020; McLaren and Markusson, 2020). These trends are escalating how terrestrial environments have been made thinkable and practicable as operating spaces for CDR, and reinforcing the legitimacy of CDR as a response to climate change. Throughout, we refer to the dangers of hype and over-promising—by which we intend both the everyday meaning of exaggerative promotion, as well as the processes by which speculative, evolving assessments implicitly or intentionally support novel technologies (e.g., Brown et al., 2000).

But the technical and political feasibility of BECCS has come under deep questioning. Furthermore, there are concerns that BECCS is politically useful precisely as an idea; permitting mitigation pathway modeling and policy rhetoric to expand the (near-term) carbon budget (Carton et al., 2020). Meanwhile, planning around eventual carbon removal could become yet another factor in delaying decarbonization. Hence, we maintain BECCS and tCDR as a guiding comparison–but our interest is on how mCDR could come to prominence, and what kind of governance would be needed to ensure that on balance, mCDR supports rather than undermines opportunities for decarbonisation and sustainable development.

Modeling Pathways

BECCS features heavily in mitigation pathways of the IPCC's Fifth Assessment Report and Special Report on 1.5C–projected by cost-optimizing integrated assessment models (IAMs)–for both technical and political rationales (van Beek et al., 2020). Most CDR technologies consume energy, while in some configurations BECCS increases availability of energy. Moreover, because both bioenergy and CCS were already included in IAMs, it was an easier task for modelers to expand their applications–crucially, in a modified and optimistic form. In reality, applications are less effective, need more space, and are combined with enhanced oil recovery (EOR) (GCCS, 2017; Fuss et al., 2018). Politically, modeling BECCS helps achieve target carbon budgets more cheaply by delaying costly near-term emissions reduction and replacing it with CDR whose future costs are discounted (Rogelj et al., 2019; McLaren, 2020).

But significant limits to tCDR are already foreseen, especially in land competition for biomass production (Smith et al., 2019; Doelman et al., 2020). As carbon budgets deplete, IAM work could instead adopt mBECCS: biomass taken from marine sources (i.e., Hughes et al., 2012) would maintain BECCS' advantage as an energy gain. Alternatively, other mCDR options might suggest new co-benefits. Blue carbon–e.g., seagrass or mangrove restoration–could sequester carbon while extending underwater natural habitats and increasing biodiversity (Hejnowicz et al., 2015; Vierros, 2017). Ocean alkalinization potentially removes large amounts of carbon due to large available surface (e.g., Kheshgi, 1995; Hartmann et al., 2013; Keller et al., 2014; Ferrer-Gonzalez and Ilyina, 2015; Renforth and Henderson, 2017), while at the same time directly counteracting ocean acidification (Keller et al., 2018). Oceans suggest huge prospective scale and leverage in modeling approaches (Resplandy et al., 2019). Yet, the technical and social feasibility of using this potential is debatable (Bindoff et al., 2019; GESAMP, 2019).

Ideally, before mCDR approaches are considered in future IAM pathway development, insights from earth system modeling (ESM) should be incorporated. While IAMs have now been coupled with more comprehensive Land-Surface Models that (albeit partially) account for uncertainties surrounding tCDR measures, this was not the case when the modeling of BECCS at large scale began. Even now, most IAMs still only use highly simplistic models to account for ocean-based carbon and heat uptake (Nicholls et al., 2020), and do not account for ocean biogeochemistry at all. An IAM minimally requires only parameters for carbon uptake potential and cost. Additional system-level feedbacks from ESMs–like leakage of CO₂ from the ocean to the atmosphere–can be incorporated in IAMs using aggregate emulators, but the magnitude is still subject to large uncertainties (Keller et al., 2018). In summary, mCDR could be implementable in IAMs, but through highly simplified renderings.

Given these considerations, it is unclear whether IAMs might trigger similar hype over mCDR. Yet if mCDR was included in IAMs, the physical uncertainties involved would be sidelined by the IAM imperative toward producing cost-optimized mitigation pathways over time. And modeling could yet inflate an mCDR bubble initiated elsewhere.

Climate Policy and Politics

The introduction of BECCS into modeled pathways was facilitated by a change in how climate targets were expressed: via “carbon budgets.” tCDR—relying on novel anthropogenic removals as well as on enhancement of natural sinks—has gained disproportionate importance as an essential mechanism to stabilize atmospheric CO₂ at concentrations compatible with the 2°C target (McLaren and Markusson, 2020).

The Paris Agreement has since cemented two critical roles for CDR. First, the 1.5°C aspiration brought CDR-heavy pathways to the fore as a way to further stretch the near-term carbon budget: a time-buying (Low and Boettcher, 2020) or stopgap strategy (Buck et al., 2020a) to ease impacts for vulnerable industries and populations during low carbon transitions. Second, the commitment to achieve Net Zero from “a balance of sources and sinks” makes CDR essential for capturing residual emissions accumulating in the atmosphere from the (transitioning) carbon economy (Morrow et al., 2020). CDR arguably underpins a green transition at both ends: highly desirable to wean the economy off carbon dependence today, and essential to clean up what carbon is left in the atmosphere afterward (Buck, 2019).

Parallel to these developments, the role of the oceans has been becoming increasingly central to international climate policy discussions. At COP 21, 23 UNFCCC parties issued the “Because the Ocean” declaration, claiming the Paris Agreement was too land-centric (Because the Ocean, 2015). A second “Because the Ocean” declaration was signed at COP 22 in 2016 by 39 countries, and an agreement was reached to give greater attention to the ocean at subsequent COPs (Because the Ocean, 2016). Recent policy-focused analyses have highlighted opportunities for ocean-based climate action in Nationally Determined Contributions (NDCs) (Gallo et al., 2017) and emphasized “ocean solutions” (e.g., Gattuso et al., 2018, 2021) and an assessment of ocean-based climate strategies was included in in Chapter 5 of the 2019 IPCC Special Report on Ocean and Cryosphere in a Changing Climate (Bindoff et al., 2019).

Whether terrestrial or marine, CDR does not have to be delivered at scale in order to exert perverse effects in climate governance. Rather, CDR may already be powerful as a promise that ongoing emissions can be reversed (Geden, 2016). Rhetoric on scaling up carbon sinks bridges the gap in reality between slow progress and future aspirations for climate action. In this sense, it may prematurely promise a “technological fix”—a technological solution to an otherwise intractable political problem (Nightingale et al., 2019). Indeed, CDR has the potential—if not guarded against in research and governance—to follow in the tracks of Kyoto Protocol-era carbon trading and offset schemes, carbon capture and storage, biofuels, shale gas, and other sociotechnical options in climate governance in which rationales and avenues for delaying and disincentivizing deep emissions cuts have emerged (Carton et al., 2020; Low and Boettcher, 2020; McLaren and Markusson, 2020).

Nonetheless, CDR loses credibility if it becomes implausible within modeling or real-world constraints. There is precedent: buying time with CCS—which has yet to be implemented at a globally-meaningful scale despite a history of over-promising (Krüger, 2017; Røttereng, 2018)—has now had to be further supplemented by CDR and BECCS (McLaren and Markusson, 2020). And now, projections of the adverse impacts of BECCS at scale may be causing it to lose credibility in both models and in political discussions. Without a credible prospect of large-scale CDR, this mutually-reinforcing complex of targets and modeling (Geden, 2016) will come under stress to generate emergency action, or find a new technology or strategy to enable continued time-buying.

CDR advocates might also hope to escape the limits that sovereign territories impose on land-bound techniques. It might be tempting for global powers or big business, pursuing neoliberal politics, to treat the “high seas” as a new frontier for overuse and exploitation (Mansfield, 2004). Existing opportunities could entrench such geopolitical and commercial moves. Providing new sinks for integration into carbon markets, following established logics and instruments for carbon offsetting and trading, may be attractive both commercially and politically (Schneider et al., 2019). Opportunities surrounding still-immature “bridging” fuels, such as algae-for-oil and marine biofuels, may be influential (Maeda et al., 2018)—even though such deployments can undermine potential for long-term carbon storage (McLaren, 2020). And actors may seek to strategically position themselves for further exploitation of resources such as minerals and fisheries in the “blue economy.”

Innovation and Industry

The idea of the “blue economy” emerged from Rio+20 (Voyer et al., 2018), and mCDR arises in this context. The story of terrestrial limits being transcended through development of marine frontiers is already mapped out for aquaculture (the “blue revolution” to bring cultivation to oceanic space), biofuels, and mineral and resource extraction (deep-sea mining); it follows a “blue growth” logic, as the availability of land and land-based resources seems foreclosed. Discourses prevalent in the blue economy–oceans as natural capital, as good business, as integral to small island developing states, as small-scale fisheries (ibid.)–are all present in the umbrella concept of mCDR.

This connection with the blue economy implies different sorts of actor coalitions than feature in tCDR, and perhaps different rationales. Coalitions may include ocean conservation organizations concerned with the dire state of the oceans (e.g., Blue Carbon Initiative (BCI), 2012; World Wildlife Fund (WWF), 2021a,b), as well as firms developing ocean sensing and monitoring technologies (e.g., Solid Carbon, 2020; Ocean Networks Canada, 2021). In the US and Germany, key oceanic research institutes and networks are developing road maps citing “enormous potential” (Oceans Visions Alliance, 2021) and “sustainable utilization” of mCDR (Deutsche Allianz Meeresforschung (DAM), 2020), and some seek to explore the potentials of commercial viability. Insofar as the ocean is perceived as both “a new economic and epistemological frontier” (Ertör and Hadjimichael, 2020), new rationales for urgency and experimentation with mCDR may emerge.

However, the seas are not an empty frontier, but busy (Bennett, 2019), which will near-inevitably lead to ocean use conflicts. Marine spatial planning may be able to optimize interactions between carbon removal and other ocean uses (Boucquey et al., 2016). However, if local opposition to ocean exploitation on other fronts grows, this could be detrimental to the prospects of mCDR. Already there are concerns about displacement of coastal communities, “ocean grabbing,” and privatization of seas and coastlines (Barbesgaard, 2018; Ertör and Hadjimichael, 2020).

Under a commercial orientation of research and development, mCDR is likely to be hyped, to attract venture capital. But venture capitalists have their own agenda, and the demands of investors for early profitability and “exit” (a trade sale or initial public offering allowing investors to recover their stakes) push green-tech down predictable paths (Buck, 2016 on tCDR specifically; Goldstein, 2018). Inventors are sidelined in favor of experienced financial and business managers, and long-term ambitions to transform society with disruptive technology are shelved in favor of configurations that can deliver profitable incremental gains in existing sectors. We should recall CCS and BECCS, where EOR dominates real-world applications, rather than long-term storage, despite optimistic scientific and commercial roadmaps (GCCS, 2017; Fuss et al., 2018).

While commercial interests may drive speculation and investment in mCDR, it is not likely to get very far without strong regulation and investment by the state, which can provide incentives and infrastructure. Carbon markets will matter in determining the fate of carbon captured in mCDR, but so will utilization opportunities and marketable “co-benefits.” Endeavors such as the non-profit Project Vesta, for enhanced weathering in coastal environments (Project Vesta, 2021), or the philanthropically funded Ocean CDR knowledge hub (Ocean CDR, 2021), are founded by entrepreneurs or are designed to appeal to entrepreneurs, even though recognized market protocols for the forms of mCDR they explore have not fully emerged yet. Moreover, the entrepreneurial discourse tends to retain an amnesia about failed commercial attempts surrounding the introduction of ocean iron fertilization into voluntary markets (Strong et al., 2015). And large-scale offshore CCS projects (Southern States Energy Board (SSEB), 2021; Northern Lights, n.d.) seem likely to require expensive infrastructures dependent on state support and partnerships.

Law and Governance

In contrast to state-regulated tCDR spaces, the ocean could be framed as comparatively free from regulation. Nevertheless, legally, the ocean is not an “open frontier.” Coastal states' laws may regulate mCDR in their territorial sea (UNCLOS, art 2, 3) and exclusive economic zone (EEZ) where states have limited sovereign rights concerning natural resources, environmental protection and scientific research (ibid., art 56, 57). Numerous international regimes also provide rules regarding marine scientific research and environmental protection that are pertinent to mCDR in all marine jurisdictions. Key regimes include the Convention on the Law of the Sea (UNCLOS, Part XII, XIII) and the London Protocol for the Dumping of Waste at Sea (Brent et al., 2019).

There is, however, a significant governance gap regarding the utilization of the ocean as a carbon sink. The Paris Agreement adopted de facto limits for atmospheric CO₂ concentrations, but no such limits exist for ocean CO₂ uptake (Stephens, 2015). Preliminary attempts to govern mCDR through the 2013 amendment to the London Protocol (Brent et al., 2019) aim to prevent environmental harm rather than regulate common use of the ocean for carbon drawdown. The prospect of mCDR as part of the “blue economy” raises significant questions about governing the ocean as a carbon sink, not only regarding environmental protection but also equal access and benefit-sharing for developing states. Taken on its own, this governance gap could suggest that this common resource is free to exploit. However, other rights and obligations in international ocean governance must still be considered—making different interpretations regarding mCDR possible.

For example, a state might conduct ocean alkalinization in territorial waters to minimize the effects of ocean acidification on coastal ecosystems, and associated tourism and shellfish industries (Renforth and Henderson, 2017). This activity would primarily be for the purpose of marine environmental protection, but could also result in CO₂ drawdown. Commercial interests and marketable co-benefits could play a role, especially if financial incentives were in place. The state responsible may claim the activity is consistent with international obligations to mitigate climate change and protect the marine environment (i.e., UNCLOS art 192), as well as their exclusive sovereign rights within their territorial sea (UNCLOS, art 2). However, other states could claim the OA activity is inconsistent with international law or require cooperation and coordination between states, especially if there is the risk of significant transboundary harm or impacts on the marine environment.

In addition to conflicting legal interpretations, this hypothetical example highlights broader tensions between different paradigms of ocean governance: the traditional focus on individual sovereign rights, vs. a more modern direction toward international cooperation and the safeguarding of the ocean as a common interest (Tanaka, 2019). Although still emerging, this second paradigm further weighs against any presumptions that states have unlimited sovereign rights in their own waters or absolute freedom in high seas areas to conduct mCDR. On balance, international oceans governance may discourage states, and by extension their citizens and corporations, from considering mCDR to be a convenient policy option.

Charting a Course

Tracking developments within and between these “frontiers” gives a more holistic picture of the contexts and activities through which marine environments are being imagined as enhanced carbon sinks, and the potentials and risks of mCDR are becoming understood (Figure 2). Unlike BECCS, mCDR is emerging less from a high-level modeling-policy complex (sections Modeling Pathways and Climate Policy and Politics), and more from innovation projects that pose co-benefits and conflicts between ocean protection, economy, and climate (section Innovation and Industry). Moreover, mCDR's “global commons” dimensions could serve as a springboard for more coordinated international governance (section Law and Governance). This mapping is double-edged: some possibilities are exploitative or delay decarbonization, while others present co-benefits underpinned by international legal obligations.

FIGURE 2

Figure 2. Emerging frontiers for the governance of marine carbon dioxide removal (mCDR) options.

Let us consider the emergence of perverse logics in the research and governance of mCDR, and project a future to be avoided. In global modeling assessments, mCDR approaches bridge the growing gap between the Paris targets and mitigation efforts, as tCDR capacities run up against biophysical and techno-economic limits. Net Zero commitments spread further, with promised investments into patchworks of ecosystems management and industrial-scale approaches, and with an eye to integrating mCDR with carbon offsets and markets. These ambitions facilitate a spectrum of mCDR projects pushed in innovation circles under uneven regulation. The projects cite co-benefits between ocean protection and business, but create phantom commodities (ultimately proving unscalable) as investment sinks for governments and venture capitalists. Few removals are delivered, and many of those are deployed as offsets for continued emissions, or as stopgaps for carbon infrastructures. Meanwhile, international law produces contested implications for how to balance the right to use the oceanic commons as a carbon sink with the obligation of marine protection.

But we can imagine a different future, harnessing opportunities on these frontiers. Optimism for delivery of mCDR in line with climate and development goals demands careful steps to prevent hype and over-promising from these opportunities, including reforms in modeling practices, policy development, innovation funding and legal governance.

Parallels can be drawn directly with tCDR debates. To avoid unrealistic evaluation of future mCDR availabilities through limited treatments of techno-economic “feasibility” (Forster et al., 2020; Thoni et al., 2020), mitigation pathways and scientific roadmaps could be tempered with widespread, localized engagements on a range of mCDR projects, exploring the conditions that breed social resistance and commercial orientations that divert carbon away from long-term storage (Buck et al., 2020b; Low and Buck, 2020; Cox et al., 2021). Updates to Paris-mandated Nationally Determined Contributions must be wary of feeding mCDR into carbon offsetting and trading. Ongoing intergovernmental negotiations over Paris' Article 6 on potential market mechanisms could separate targets and processes for emissions reduced from decarbonization vs. those from CDR, forestalling double-counting (McLaren et al., 2019).

Governance can also harness conditions that differentiate marine from terrestrial spaces. Effective governance of the seas could be informed by existing transnational frameworks for governing aquaculture, marine food resources, and marine renewables, as well as from managing the seas for conservation. Cross-sectoral marine governance therefore offers opportunities: ocean conservation organizations could partner with research initiatives and innovation efforts. In the legal sphere, the right to use and the obligation to protect the ocean could be combined in novel co-benefits. States–working with research and environmental networks and commercial entities–could ensure that mCDR is in line with their international obligations to mitigate climate change and protect the oceans (e.g., from acidification), and their national right to use ocean resources as part of a “blue growth” strategy.

Data Availability Statement

The original contributions generated for the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Author Contributions

All authors contributed equally to the conceptualizing, writing, and editing of this perspective.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

References

Barbesgaard, M. (2018). Blue growth: saviour or ocean grabbing. J. Peasant Stud. 45, 130–149. doi: 10.1080/03066150.2017.1377186

CrossRef Full Text | Google Scholar

Because the Ocean (2015). First Declaration. Available online at: https://www.becausetheocean.org/first-because-the-ocean-declaration/ (accessed March 15, 2021).

Because the Ocean (2016). Second Declaration. Available online at: https://www.becausetheocean.org/second-because-the-ocean-declaration/ (accessed March 15, 2021).

Bennett, N. J. (2019). In political seas: engaging with political ecology in the ocean and coastal environment. Coast. Manag. 47, 67–87. doi: 10.1080/08920753.2019.1540905

CrossRef Full Text | Google Scholar

Bindoff, N. L., W. W. L., Cheung, J. G., Kairo, J., Arístegui, V. A., Guinder, R., et al. (2019). Chapter 5, p. 447-587 in IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. WMO/UNEP.

Google Scholar

Blue Carbon Initiative (BCI) (2012). Available online at: http://bluecarbonportal.org/wp-content/uploads/downloads/2012/09/Lawrence_WWF_Blue-Carbon_2012.pdf (accessed March 15, 2021).

Boucquey, N., Fairbanks, L., St. Martin, K., Campbell, L. M., and McCay, B. (2016). The ontological politics of marine spatial planning: assembling the ocean and shaping the capacities of “Community” and ‘”Environment.” Geoforum 75, 1–11. doi: 10.1016/j.geoforum.2016.06.014

CrossRef Full Text | Google Scholar

Brent, K., Burns, W., and McGee, J. (2019). Governance of Marine Geoengineering. Waterloo, ON: Centre for International Governance Innovation. Available online at: https://www.cigionline.org/sites/default/files/documents/MarineGov-web.pdf (accessed May 10, 2021).

Google Scholar

Brown, N., Rappert, B., and Webster, A. (eds.). (2000). Contested Futures: A Sociology of Prospective Techno-Science. Aldershot: Ashgate.

Google Scholar

Buck, H. J. (2016). Rapid scale up of negative emissions technologies: social barriers and social implications. Clim. Change 139, 155–167. doi: 10.1007/s10584-016-1770-6

CrossRef Full Text | Google Scholar

Buck, H. J. (2019). After Geoengineering: Climate Tragedy, Repair, and Restoration. New York, NY: Verso.

Google Scholar

Buck, H. J., Fuhrman, J., Morrow, D. R., Sanchez, D. L., and Wang, F. M. (2020b). Carbon removal and adaptation. One Earth 3. 425–435. doi: 10.1016/j.oneear.2020.09.008

CrossRef Full Text | Google Scholar

Buck, H. J., Martin, L. J., Geden, O., Kareiva, P., Koslov, L., Krantz, W., et al. (2020a). Evaluating the efficacy and equity of environmental stopgap measures. Nat. Sustain. 3, 499–504. doi: 10.1038/s41893-020-0497-6

CrossRef Full Text | Google Scholar

Carton, W., Asiyanbi, A., Beck, S., Buck, H. J., and Lund, J. F. (2020). Negative emissions and the long history of carbon removal. Wiley Interdiscip. Rev. Clim. Change 11:e671. doi: 10.1002/wcc.671

CrossRef Full Text | Google Scholar

Cox, E., Boettcher, M., Spence, E., and Bellamy, R. (2021). Casting a wider net on Ocean NETs. Front. Clim. 3:576294. doi: 10.3389/fclim.2021.576294

CrossRef Full Text | Google Scholar

Deutsche Allianz Meeresforschung (DAM) (2020). 19 Leading German Marine Institutions in One Alliance. Available online at: https://www.allianz-meeresforschung.de/en/ (accessed January 27, 2021).

Doelman, J. C., Stehfest, E., van Vuuren, D. P., Tabeau, A., Hof, A. F., Braakhekke, M. C., et al. (2020). Afforestation for climate change mitigation: potentials, risks, and trade-offs. Glob. Change Biol. 26, 1576–1591. doi: 10.1111/gcb.14887

PubMed Abstract | CrossRef Full Text | Google Scholar

Ertör, I., and Hadjimichael, M. (2020). Blue degrowth and the politics of the sea: rethinking the blue economy. Sustain, Sci. 15, 1–10. doi: 10.1007/s11625-019-00772-y

CrossRef Full Text | Google Scholar

Ferrer-Gonzalez, M., and Ilyina, T. (2015). “Mitigation potential, risks, and side-effects of ocean alkalinity enhancement,” in Deglaciation Changes in Ocean Dynamics and Atmospheric CO₂, eds M. Sarnthein and G. H. Haug (Halle: German Academy of Sciences Leopoldina-National Academy of Sciences), 275–278.

Google Scholar

Forster, J., Vaughan, N. E., Gough, C., Lorenzoni, I., and Chilvers, J. (2020). Mapping feasibilities of greenhouse gas removal: key issues, gaps, and opening up assessments. Glob. Environ. Change 63:102073. doi: 10.1016/j.gloenvcha.2020.102073

CrossRef Full Text | Google Scholar

Fuss, S., Lamb, W. F., Callaghan, M. W., Hilaire, J., Creutzig, F., Amann, T., et al. (2018). Negative emissions—Part 2: costs, potentials, and side effects. Environ. Res. Lett. 13:063002. doi: 10.1088/1748-9326/aabf9f

CrossRef Full Text | Google Scholar

Gallo, N. D., Victor, D. G., and Levin, L. A. (2017). Ocean commitments under the Paris agreement. Nat. Clim. Change 7, 833–838. doi: 10.1038/nclimate3422

CrossRef Full Text | Google Scholar

Gattuso, J.-P., Magnan, A. K., Bopp, L., Cheung, W. W. L., Duarte, C. M., Hinkel, J., et al. (2018). Ocean solutions to address climate change and its effects on marine ecosystems. Front. Mar. Sci. 5:337. doi: 10.3389/fmars.2018.00337

PubMed Abstract | CrossRef Full Text | Google Scholar

Gattuso, J.-P., Williamson, P., Duarte, C. M., and Magnan, A. K. (2021). The potential for ocean-based climate action: negative emission technologies and beyond. Front. Clim. 2:575716. doi: 10.3389/fclim.2020.575716

CrossRef Full Text | Google Scholar

GCCS (2017). The Global Status of CCS: 2017. Canberra, ACT: Global CCS Institute.

Google Scholar

Geden, O. (2016). The Paris Agreement and the inherent inconsistency of climate policymaking. Wiley Interdiscip. Rev. Clim. Change 7, 790–797. doi: 10.1002/wcc.427

CrossRef Full Text | Google Scholar

GESAMP (2019). “High level review of a wide range of proposed marine geoengineering techniques,” in Rep. Stud. GESAMP No. 98, (IMO/FAO/UNESCO-IOC/UNIDO/WMO/IAEA/UN/UN Environment/ UNDP/ISA Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection), eds P. W. Boyd and C. M. G. Vivian (London: International Maritime Organization), 144p.

Google Scholar

Goldstein, J. (2018). Planetary Improvement: Cleantech Entrepreneurship and the Contradictions of Green Capitalism. Cambridge, MA: The MIT Press.

Google Scholar

Hartmann, J., West, A. J., Renforth, P., Köhler, P., De La Rocha, C. L., Wolf-Gladrow, D. A., et al. (2013). Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Rev. Geophys. 51, 113–149. doi: 10.1002/rog.20004

CrossRef Full Text | Google Scholar

Hejnowicz, A. P., Kennedy, H., Rudd, M. A., and Huxham, M. R. (2015). Harnessing the climate mitigation, conservation, and poverty alleviation potential of seagrasses: prospects for developing blue carbon initiatives and payment for ecosystem service programmes. Front. Mar. Sci. 2:32. doi: 10.3389/fmars.2015.00032

CrossRef Full Text | Google Scholar

Hughes, A. D., Black, K. D., Campbell, I., Davidson, K., Kelly, M. S., and Stanley, M. S. (2012). Does seaweed offer a solution for bioenergy with biological carbon capture and storage? Greenh. Gases 2, 402–407. doi: 10.1002/ghg.1319

CrossRef Full Text | Google Scholar

Keller, D. P., Feng, E. Y., and Oschlies, A. (2014). Potential climate engineering effectiveness and side effects during a high carbon dioxide-emission scenario. Nat. Commun. 5, 1–11. doi: 10.1038/ncomms4304

PubMed Abstract | CrossRef Full Text | Google Scholar

Keller, D. P., Lenton, A., Scott, V., Vaughan, N. E., Bauer, N., Ji, D., et al. (2018). The Carbon Dioxide Removal Model Intercomparison Project (CDRMIP): rationale and experimental protocol for CMIP6. Geosci. Model Dev. 11, 1133–1160. doi: 10.5194/gmd-11-1133-2018

CrossRef Full Text | Google Scholar

Kheshgi, H. S. (1995). Sequestering atmospheric carbon dioxide by increasing ocean alkalinity. Energy 20, 915–922. doi: 10.1016/0360-5442(95)00035-F

CrossRef Full Text | Google Scholar

Krüger, T. (2017). Conflicts over carbon capture and storage in international climate governance. Energy Policy 100, 58–67. doi: 10.1016/j.enpol.2016.09.059

CrossRef Full Text | Google Scholar

Low, S., and Boettcher, M. (2020). Delaying decarbonization: climate governmentalities and sociotechnical strategies from copenhagen to Paris. Earth Syst. Gov. 5:100073. doi: 10.1016/j.esg.2020.100073

CrossRef Full Text | Google Scholar

Low, S., and Buck, H. J. (2020). The practice of responsible research and innovation in “climate engineering.” WIREs Clim. Change 11:e644. doi: 10.1002/wcc.644

CrossRef Full Text | Google Scholar

Maeda, Y., Yoshino, T., Matsunaga, T., Matsumoto, M., and Tanaka, T. (2018). Marine microalgae for production of biofuels and chemicals. Curr. Opin. Biotechnol. 50, 111–120. doi: 10.1016/j.copbio.2017.11.018

PubMed Abstract | CrossRef Full Text | Google Scholar

Mansfield, B. (2004). Neoliberalism in the oceans: “rationalization,” property rights, and the commons question. Geoforum 35, 313–326. doi: 10.1016/j.geoforum.2003.05.002

CrossRef Full Text | Google Scholar

McLaren, D. P. (2020). Quantifying the potential scale of mitigation deterrence from greenhouse gas removal techniques. Clim. Change 162, 2411–2428. doi: 10.1007/s10584-020-02732-3

CrossRef Full Text | Google Scholar

McLaren, D. P., and Markusson, N. O. (2020). The co-evolution of technological promises, modelling, policies, and climate change targets. Nat. Clim. Change 10, 392–397. doi: 10.1038/s41558-020-0740-1

CrossRef Full Text | Google Scholar

McLaren, D. P., Tyfield, D. P., Willis, R., Szerszynski, B., and Markusson, N. O. (2019). Beyond “Net-Zero”: a case for separate targets for emissions reduction and negative emissions. Front. Clim 1:4. doi: 10.3389/fclim.2019.00004

CrossRef Full Text | Google Scholar

Morrow, D. R., Thompson, M. S., Anderson, A., Batres, M., Buck, H. J., Dooley, K., et al. (2020). Principles for thinking about carbon dioxide removal in just climate policy. One Earth 3, 150–153. doi: 10.1016/j.oneear.2020.07.015

CrossRef Full Text | Google Scholar

Nicholls, Z. R. J., Meinshausen, M., Lewis, J., Gieseke, R., Dommenget, D., Dorheim, K., et al. (2020). Reduced complexity model intercomparison project phase 1: introduction and evaluation of global-mean temperature response. Geosci. Model Dev. 13, 5175–5190. doi: 10.5194/gmd-13-5175-2020

CrossRef Full Text | Google Scholar

Nightingale, A. J., Eriksen, S., Taylor, M., Forsyth, T., Pelling, M., Newsham, A., et al. (2019). Beyond technical fixes: climate solutions and the great derangement. Clim. Dev. 12, 343–352. doi: 10.1080/17565529.2019.1624495

CrossRef Full Text | Google Scholar

Northern Lights (n.d.). About the Project. Available online at: https://northernlightsccs.com/en/about (accessed January 27 2021).

Google Scholar

Ocean CDR (2021). The leading knowledge Hub on Ocean-Based Carbon Dioxide Removal. Available online at: https://oceancdr.net/ (accessed January 27, 2021).

Ocean Networks Canada (2021). Discover the Ocean. Understand the Planet. Available online at: https://www.oceannetworks.ca/innovation-centre/smart-ocean-systems (accessed January 27, 2021).

Oceans Visions Alliance (2021). Transforming Science and Engineering Into Ocean Solutions. Available online at: https://www.oceanvisions.org/ (accessed January 27, 2021).

Project Vesta (2021). Could This Rock Reverse Climate Change? Available online at: https://www.projectvesta.org/ (accessed January 27, 2021).

Renforth, P., and Henderson, G. (2017). Assessing ocean alkalinity for carbon sequestration. Rev. Geophys. 55, 636–674. doi: 10.1002/2016RG000533

CrossRef Full Text | Google Scholar

Resplandy, L., Keeling, R. F., Eddebbar, Y., Brooks, M., Wang, R., Bopp, L., et al. (2019). Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition. Sci. Rep. 9:20244. doi: 10.1038/s41598-019-56490-z

PubMed Abstract | CrossRef Full Text | Google Scholar

Rogelj, J., Huppmann, D., Krey, V., Riahi, K., Clarke, L., Gidden, M., et al. (2019). A new scenario logic for the Paris Agreement long-term temperature goal. Nature 573, 357–363. doi: 10.1038/s41586-019-1541-4

PubMed Abstract | CrossRef Full Text | Google Scholar

Røttereng, J.-K. S. (2018). The comparative politics of climate change mitigation measures: who promotes carbon sinks and why? Glob. Environ. Polit. 18, 52–75. doi: 10.1162/GLEP_a_00444

CrossRef Full Text | Google Scholar

Royal Society/Royal Academy of Engineering (RS/RAE) (2018). Greenhouse Gas Removal. Available online at: https://royalsociety.org/-/media/policy/projects/greenhouse-gas-removal/royal-society-greenhouse-gas-removal-report-2018.pdf (accessed March 15, 2021).

Google Scholar

Schneider, L., Duan, M., Stavins, R., Kizzier, K., Broekhoff, D., Jotzo, F., et al. (2019). Double counting and the Paris Agreement rulebook. Science 366, 180–183. doi: 10.1126/science.aay8750

PubMed Abstract | CrossRef Full Text | Google Scholar

Smith, P., Adams, J., Beerling, D. J., Beringer, T., Calvin, K. V., Fuss, S., et al. (2019). Impacts of land-based greenhouse gas removal options on ecosystem services and the United Nations sustainable development goals. Annu. Rev. Environ. Resour. 44, 255–286. doi: 10.1146/annurev-environ-101718-033129

CrossRef Full Text | Google Scholar

Solid Carbon (2020). Solid Carbon: A Negative Emissions Solution. Available online at: https://www.solidcarbon.ca/ (accessed January 27, 2021).

Southern States Energy Board (SSEB) (2021). SECARB Offshore. Available online at: https://www.sseb.org/programs/offshore/ (accessed January 27, 2021).

Stephens, T. (2015). “Ocean acidification,” in Research Handbook on International Marine Environmental Law, ed R. Rayfuse (Cheltenham: Edward Elgar Publishing). 431–450.

Google Scholar

Strong, A. L., Cullen, J. J., and Chisholm, S. W. (2015). Ocean fertilization: science, policy, and commerce. Oceanography 22, 236–261. doi: 10.5670/oceanog.2009.83

CrossRef Full Text | Google Scholar

Tanaka, Y. (2019). The International Law of the Sea, 3rd Edn. Cambridge: Cambridge University Press.

Google Scholar

Thoni, T., Beck, S., Borchers, M., Förster, J., Görl, K., Hahn, A., et al. (2020). Deployment of negative emissions technologies at the national level: a need for holistic feasibility assessments. Front. Clim. 2:590305. doi: 10.3389/fclim.2020.590305

CrossRef Full Text | Google Scholar

van Beek, L., Hajer, M., Pelzer, P., van Vuuren, D. P., and Cassen, C. (2020). Anticipating futures through models: integrated assessment modeling in the climate science-policy interface since 1970. Glob. Environ. Change 65:102191. doi: 10.1016/j.gloenvcha.2020.102191

CrossRef Full Text | Google Scholar

Vierros, M. (2017). Communities and blue carbon: the role of traditional management systems in providing benefits for carbon storage, biodiversity conservation and livelihoods. Clim. Change 140, 89–100. doi: 10.1007/s10584-013-0920-3

CrossRef Full Text | Google Scholar

Voyer, M., Quirk, G., McIlgorm, A., and Azmi, K. (2018). Shades of blue: what do competing interpretations of the Blue Economy mean for oceans governance? J. Environ. Policy Plan. 20, 595–616. doi: 10.1080/1523908X.2018.1473153

CrossRef Full Text | Google Scholar

World Wildlife Fund (WWF) (2021a). World Wildlife Fund. Available online at: https://www.worldwildlife.org/projects/incorporating-blue-carbon-in-kenya-s-national-green-house-gas-accounting (accessed March 15, 2021).

Google Scholar

World Wildlife Fund (WWF) (2021b). Available online at: https://www.wwf.org.uk/ocean-heroes/uk-seas (accessed March 15, 2021).