Discussions regarding the potential role of blue carbon under the United Nations Framework Convention on Climate Change (UNFCCC) have been active (Murray et al., 2012; Herr et al., 2011). However, no specific mechanism dedicated solely to blue carbon currently exists within the UNFCCC framework. Since COP 25 established the the “Ocean and Climate Change Dialogue” and COP 27 encouraged Parties to integrate ocean actions into their national plans, a new institutional context has been created, within which blue carbon may potentially fall under the following categories: the Kyoto Protocol, the Durban Platform, and the Paris Agreement (IUCN and CI, 2023; Herr and Landis, 2016; Lecerf et al., 2023).

First, blue carbon may be associated with two provisions of the Kyoto Protocol: (1) accounting for sources and removals by sinks from land use, land-use change and forestry (LULUCF) at the national level, and (2) the Clean Development Mechanism (IUCN and CI, 2023). Firstly, Article 3.3 and 3.4 of the Kyoto Protocol stipulate that, prior to each session, each Party shall report for consideration by the Subsidiary Body for Scientific and Technological Advice data on the net changes in its emissions and removals by sinks of greenhouse gases resulting from direct human-induced land-use change and forestry activities, limited to afforestation, reforestation and deforestation (UNFCCC, 1997). Mangroves, as tidal forests, have been included within the LULUCF since the adoption of the Kyoto Protocol. Secondly, the Kyoto Protocol also established a Clean Development Mechanism to assist Parties not included in it in achieving sustainable development and contributing to the ultimate objective of the Convention, and to assist Parties included in its Annex I in achieving compliance with their quantified emission limitation and reduction commitments under Article 3 (UNFCCC, 1997). However, since its inception, the only LULUCF activity type approved under the CDM has been afforestation and reforestation (UNFCCC, 2015). In June 2011, at its 61st meeting, the CDM Executive Board adopted the large-scale A/R methodology AR-AM0014 “Afforestation and Reforestation of Degraded Mangrove Habitats”, establishing a specific A/R methodology category applicable to mangrove habitats (UNFCCC, 2011a). This approval set a precedent for the inclusion of blue carbon within the CDM (IPBC, 2021).

Secondly, the two mechanisms under the Durban Platform relevant to blue carbon are Reducing Emissions from Deforestation and Forest Degradation (REDD+) and Nationally Appropriate Mitigation Actions (NAMAs) (IPBC, 2021). In December 2011, the 17th session of the Conference of the Parties (COP 17) to the UNFCCC was held in Durban, South Africa. The meeting produced two key decisions: first, the Kyoto Protocol would enter a second commitment period starting in 2013; second, the “Durban Platform for Enhanced Action” was launched to develop a protocol, another legal instrument, or an agreed outcome with legal force under the Convention applicable to all Parties by 2015, for implementation from 2020 onwards (UNFCCC, 2012).

“Reducing emissions from deforestation in developing countries” (RED) was initially proposed and incorporated into the UNFCCC negotiation process at COP 11 in 2005 (UNFCCC, 2006). The agreements reached at COP 16 in Cancun (2010) reaffirmed the early activities identified in the Bali roadmap and explicitly listed five activities to be included in REDD+: to contribute to mitigation actions in the forest sector, developing country Parties are encouraged, in accordance with their respective capabilities and national circumstances, to undertake the following activities: (a) reducing emissions from deforestation; (b) reducing emissions from forest degradation; (c) conservation of forest carbon stocks; (d) sustainable management of forests; and (e) enhancement of forest carbon stocks (UNFCCC, 2011b). At COP 17 in Durban (2011), agriculture was also proposed as a potential sectoral pathway (UNFCCC, 2012). In recent years, REDD+ has established more apparent linkages with other focus areas under the UNFCCC process. Discussions on drivers of deforestation have incorporated sectors beyond forestry, such as agriculture and mining, although no specific joint activities have been established to date. Related discussions primarily focus on alleviating pressure on forests by increasing productivity and restoring degraded lands for productive agricultural use (Olander et al., 2012).

Nationally Appropriate Mitigation Actions (NAMAs) were introduced at COP 13 in 2007 with the adoption of the Bali Action Plan. The Plan explicitly stated that developing country Parties would undertake NAMAs in the context of sustainable development, supported and enabled by technology, financing, and capacity-building, in a measurable, reportable, and verifiable (MRV) manner, as part of the subsequent negotiation framework (UNFCCC, 2008). In the context of that time, there was no closed, formal definition of NAMAs at the international level (Wienges, 2013). They were widely understood as voluntary mitigation actions by developing countries. Following the Cancun conference, differentiated MRV arrangements were established for domestically supported and internationally supported actions, and a NAMA registry was initiated to record these actions and match them with the corresponding support (O’Sullivan et al., 2011). Regarding financing and pathways, the Bali Action Plan proposed exploring various approaches (UNFCCC, 2008). The Cancun Agreements (Decision 1/CP.16) established the Green Climate Fund (GCF), whose governance and operational details were subsequently developed through the design work of the Transitional Committee in 2010 (UNFCCC, 2011). Concerning the integration of blue carbon and NAMAs, policy studies explicitly recommended that during the phase when methodologies and accounting remain under development, blue carbon could be advanced through the NAMA platform to raise its profile and financing potential, prioritizing readiness and demonstration activities — such as data collection, establishing baselines/reference emission levels, developing MRV methodologies, and piloting policies and projects (O’Sullivan et al., 2011). On a practical level, around 2011/2012, literature frequently cited examples of NAMAs related to coastal wetlands being submitted by countries including Sierra Leone, Eritrea, and Ghana (Herr et al., 2012).

Third, under the Paris Agreement, the mechanisms relevant to blue carbon include Nationally Determined Contributions (NDCs), Nature-based Solutions (NBS) and the activities involving removals under the Article 6.4 mechanism. The Paris Agreement was unanimously adopted in December 2015 by 196 Parties to the UNFCCC at COP 21. This landmark agreement marked a turning point, setting nations on a course to transition towards a low-carbon economy by harnessing innovation in technology, energy, finance, and conservation (Herr and Landis, 2016). NDCs were initially intended to articulate the actions Parties would take to achieve the mitigation objective outlined in Article 2 of the Convention — stabilizing greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system (UNFCCC, 2014). The approach requires countries to determine their own path to reducing emissions through their NDCs, with each successive NDC intended to represent a progression beyond the previous and reflecting the highest possible ambition. In 2014, during COP 20 in Lima, Peru, specified that Parties could also “consider communicating their undertakings in adaptation planning or consider including an adaptation component in their intended nationally determined contributions” (UNFCCC, 2015). Nature-based Solutions offer a promising yet often overlooked pathway for enhancing NDCs. Despite this, 14 coastal Parties to the Paris Agreement, including the United States and Australia, omitted the ocean from their initial NDCs submitted in 2016 (Gallo et al., 2017).

Additionally, there is need to include discussion of standards for carbon removal under Article 6.4 of the Paris Agreement (UNFCCC, 2024). Although no specific to blue carbon, Article 6.4 required to establish a mechanism to contribute to the mitigation of greenhouse gas emissions and support sustainable development under the athority and guidance of the CMA (UNFCCC, 2015; Kuwae et al., 2022). Operational requirements for activities involving removals are elaborated in the CMA’s rules, modalities and procedures and subsequent standards: CMA Decision 3/CMA.3 requests recommendations on “activities involving removals,” including monitoring, reporting and accounting for removals and crediting periods, addressing reversals, and avoiding leakage, while the RMP annex requires activities to minimize non-permanence and address reversals in full and to minimize and adjust for remaining leakage, and requires methodologies to address uncertainty, leakage, and reversals where applicable and to demonstrate additionality (UNFCCC, 2021). Such requirements are necessarily to establish the ‘additionality’ of climate benefits (Michaelowa et al., 2019; Bach et al., 2024) and hence the validity of associated carbon offsets: crucial issues for comparing the cost-effectiveness of different climate actions.

The Convention on Biological Diversity (CBD), as a global framework convention, does not dedicate specific Articles to particular ecosystem types. Instead, it aims to develop norms for the conservation of biological diversity and the sustainable use of its components (Ekardt et al., 2023; Hooper et al., 2012). This Convention and its related instruments are linked to climate change adaptation and mitigation efforts for two primary reasons. Firstly, Article 8(f) of the Convention explicitly mandates Parties to, as far as possible and appropriate, “rehabilitate and restore degraded ecosystems and promote the recovery of threatened species” (CBD, 1992). This provision protects blue carbon ecosystems (Herr et al., 2011). Secondly, the link is evident in numerous documented instances that acknowledge the need to integrate coastal biodiversity, including blue carbon ecosystems, into climate change mitigation strategies.

Early in the Convention’s existence, the Conference of the Parties (COP) focused on marine and coastal biodiversity. At COP 2 in 1995, a Ministerial Statement was adopted which announced a global consensus on marine and coastal biodiversity, known as the “Jakarta Mandate,” highlighting the urgency for collective action to protect marine and coastal ecosystems (IISD, 1995). Subsequently, COP 4 in 1998 formally adopted the “Programme of Work on Marine and Coastal Biological Diversity,” focusing on five key areas: integrated management of marine and coastal areas, marine living resources, marine protected areas, mariculture, and invasive alien species (CBD, 1998). This programme of work was subsequently updated in 2004 and 2010, further emphasizing the importance of coastal and marine ecosystems (CBD, 2023). Notably, the CBD Programme of Work on Marine and Coastal Biological Diversity, adopted in 1998 and reviewed and updated in 2004 and 2010, also recognized the importance of marine and coastal biodiversity in mitigating and adapting to climate change and in addressing the impacts of ocean acidification (CI et al., 2010). Consequently, within the CBD framework, blue carbon may fall under the following categories: the Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization, and the Kunming-Montreal Global Biodiversity Framework.

First, at COP 10 in Nagoya in 2010, the Strategic Plan for Biodiversity 2011-2020, along with its 20 Aichi Targets, was adopted. Aichi Target 15 explicitly integrated ecosystem carbon sinks into biodiversity goals for the first time. It stipulated: “By 2020, ecosystem resilience and the contribution of biodiversity to carbon stocks has been enhanced, through conservation and restoration, including restoration of at least 15 per cent of degraded ecosystems, thereby contributing to climate change mitigation and adaptation and to combating desertification” (CBD, 2010). This target directly acknowledged the vital role of conserving and restoring ecosystems, such as forests, wetlands, and blue carbon ecosystems, in addressing climate change. At the same COP 10, the Parties also adopted decisions on “Biodiversity and Climate Change” (Decision X/33) and “Marine and Coastal Biodiversity” (Decision X/29). Decision X/29 urged Parties to integrate coastal and marine biodiversity into national climate change adaptation and mitigation strategies and to develop ecosystem-based approaches for climate action (CBD, 2010). Decision X/33 further emphasized achieving multiple benefits through the maintenance and restoration of ecosystems, including coastal wetlands, and invited Parties to employ ecosystem-based approaches in their climate planning (Buditama, 2016). These decisions set a precedent for “climate-biodiversity” synergies under the CBD framework, positioning coastal blue carbon ecosystems as a critical area for achieving co-benefits for both biodiversity conservation and climate change mitigation globally (Farahmand et al., 2025; Herr et al., 2011). The Conference also designated the Global Environment Facility (GEF) as the financial mechanism for the Nagoya Protocol, inviting relevant countries and multilateral financial institutions to provide sufficient, predictable, and timely financial support for implementation.

Second, COP 15 in late 2022 adopted the Kunming-Montreal Global Biodiversity Framework (KM-GBF), which establishes 23 action-oriented global targets for 2030 and sets four long-term goals (A-D) for the 2050 vision (CBD, 2022). This framework places significant emphasis on the conservation and restoration of marine, coastal, and island biodiversity, aligning closely with blue carbon governance. Firstly, Target 1 calls for ensuring that all areas are under participatory, integrated, and biodiversity-inclusive spatial planning, and for reducing the loss of areas of high biodiversity importance to near zero by 2030 (CBD, 2022). This implies that carbon sink ecosystems, such as coastal wetlands and mangroves, should be integrated into land and sea spatial planning, utilizing science-based integrated coastal zone management to prevent ecological damage from land-use changes. Secondly, Target 2 requires that at least 30% of degraded terrestrial, inland water, and coastal and marine ecosystems are under effective restoration by 2030 (CBD, 2022). Consequently, degraded blue carbon ecosystems fall under the scope of this restoration target. However, the official text does not explicitly use the term “blue carbon,” leaving specific inclusion subject to national identification and planning of degraded areas. Thirdly, Target 3 calls for ensuring that by 2030, at least 30% of terrestrial, inland water, and coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem functions and services, are effectively conserved and managed through ecologically representative, well-connected systems of protected areas and other effective area-based conservation measures (OECMs), recognizing indigenous and local communities’ territories where applicable, and ensuring sustainable use is entirely consistent with conservation outcomes (CBD, 2022). Given that the degradation and loss of blue carbon ecosystems are primarily anthropogenic, with risks exacerbated by climate change (Fu et al., 2024), integrating them into protected areas and OECM networks, while ensuring the equitable participation and leadership of Indigenous Peoples and local communities (Dawson et al., 2021), is crucial. Sustained stewardship by these groups — including ecological health monitoring, erosion control, and sustainable habitat management informed by cultural traditions — can significantly enhance the success and longevity of blue carbon projects, ensuring sustained climate benefits and ecosystem service provision (Bell-James et al., 2023; Herr et al., 2017). Finally, Target 8 directly addresses climate change and biodiversity, aiming to minimize its impact and that of ocean acidification on biodiversity, and increase resilience through mitigation, adaptation, and disaster risk reduction actions, including through nature-based solutions and/or ecosystem-based approaches (CBD, 2022). Blue carbon ecosystems like mangroves, salt marshes, and, in some contexts, seagrass meadows, which accumulate substantial organic carbon stocks in their sediment soils, represent potentially important nature-based and ecosystem-based solutions (Hilmi et al., 2021; IPCC, 2019; Kauffman et al., 2020). While rising atmospheric CO₂ causes ocean acidification, the increased dissolved CO₂ can also stimulate photosynthesis in marine vegetation, potentially aiding in carbon removal from seawater and locally mitigating the impacts of acidification on biodiversity (Su et al., 2020).

Furthermore, other KM-GBF global targets provide supportive safeguards for blue carbon ecosystems. These include Target 5 (ensuring sustainable, safe, and legal use, harvesting, and trade of wild species), Target 7 (addressing pollution risks and impacts), Target 6 (managing alien invasive species), and Target 9 (ensuring sustainable management of wild species and benefits for users) (CBD, 2022). The KM-GBF also establishes essential financing and capacity-building mechanisms. Target 19 calls for substantially increasing financial resources from all sources, and Target 20 emphasizes enhancing capacity-building and development, particularly in developing countries, through various forms of cooperation to facilitate joint technology development and scientific research programmes (CBD, 2022). Overall, through its goal-setting and implementation support, the KM-GBF has effectively integrated blue carbon ecosystems into the CBD’s implementation mechanism, providing significant impetus for their restoration and conservation (Fu et al., 2024).

Discussions on the role of blue carbon within the framework of the Sustainable Development Goals (SDGs) are also gaining increasing attention (Krause-Jensen et al., 2022). In September 2015, all 193 UN Member States adopted the 2030 Agenda for Sustainable Development at a summit, establishing 17 SDGs and 169 associated targets (Baisakh, 2015). However, no standalone mechanism specifically dedicated to blue carbon exists within the SDG architecture. Functioning as a nature-based solution linking marine ecosystems and climate action, blue carbon’s contributions are primarily manifested through its support for multiple SDGs. Consequently, within the SDG framework, blue carbon can be categorized under the following aspects: i) the ocean goal (SDG 14), ii) climate action (SDG 13), iii) terrestrial ecosystem and biodiversity goals (SDG 15), while also transversally contributing to synergistic gains in poverty reduction, food security, water resources, and other targets (Sungkawati and Umali, 2024).

SDG 14 promotes the conservation and sustainable use of oceans, seas, and marine resources for sustainable development, encompassing ten targets that address aspects of marine health, conservation, and sustainable resource use (UN, 2015). Specifically, Target 14.2 mandates the sustainable management and protection of marine and coastal ecosystems to avoid significant adverse impacts. As vital components of marine and coastal ecosystems, blue carbon ecosystems – mangroves, salt marshes, and seagrass beds – play a crucial role in this protection (Chalastani et al., 2022). Furthermore, Target 14.5 aimed to conserve at least 10% of coastal and marine areas by 2020, aligning it with the CBD’s Aichi Target 11 (protecting 17% of terrestrial and 10% of marine areas) (CI et al., 2010). Although the deadline for most SDG 14 targets was 2020, in the Ministerial Declaration of the UN Economic and Social Council’s 2020 high-level segment, countries committed to upholding the integrity of the 2030 Agenda by raising their ambition and continuing action on targets with a 2020 timeline (CI et al., 2010). A noted limitation of these targets is their focus on existing industries and challenges, potentially failing to anticipate future issues arising from new potential uses of marine resources (Sturesson et al., 2018). For instance, they seldom mention emerging technologies like blue carbon and bioprospecting for new marketable products, which carry significant risks (ICSU, 2017).

SDG 14 is recognized for its cross-cutting role within the 2030 Agenda: its targets interact closely with poverty eradication (SDG 1), zero hunger (SDG 2), decent work and economic growth (SDG 8), sustainable consumption and production (SDG 12), climate action (SDG 13), and terrestrial biodiversity (SDG 15) (Sturesson et al., 2018; CESA et al., 2017). The protection and sustainable use of oceans are expected to create positive interactions with other SDGs, primarily characterized as indivisible, mutually reinforcing, and enabling (CESA et al., 2017). The nature and intensity of these interactions are dynamic and context-specific, ranging from synergistic to antagonistic trade-offs (ICSU, 2017).

SDG 13 aims to take urgent action to combat climate change and its impacts (UN, 2015). Blue carbon ecosystems, as significant natural carbon sinks and ecosystem-based climate solutions, are regarded as effective pathways achieving both mitigation and adaptation objectives (Stuchtey et al., 2020; Seddon et al., 2020; Howard et al., 2023). These coastal ecosystems sequester carbon at a significantly higher rate per hectare than most terrestrial forests and store substantial amounts of organic carbon over the long term within their sediment soils (Macreadie et al., 2013; Chalastani et al., 2022). Simultaneously, mangroves and salt marshes buffer coastlines against sea-level rise and storm surges, protecting coastal communities from extreme weather events (Chalastani et al., 2022). Therefore, protecting and restoring blue carbon ecosystems is considered integrated “mitigation + adaptation” climate action, offering a cost-effective natural solution for achieving the Paris Agreement’s temperature goal (IPCC, 2022, 2019). The Intergovernmental Panel on Climate Change (IPCC) also assesses that maintaining and enhancing coastal blue carbon ecosystems can form part of national portfolios of emission reduction and sink enhancement policies (IPCC, 2023). As of 2023, among the 158 Parties to the Paris Agreement that included an adaptation component in their NDCs, 30% identified marine ecosystems as a priority adaptation sector, and 11% set quantitative targets for fisheries and marine ecosystems. Out of 148 Parties, 56% integrated coastal and marine nature-based solutions for mitigation or adaptation into their new or updated NDCs (Friess et al., 2019). In summary, as a natural climate solution, blue carbon directly supports SDG 13 and its Target 13.2, which aims to integrate climate change measures into national policies, strategies, and planning.

Although located in coastal zones, blue carbon ecosystems also play significant roles in protecting biodiversity and supporting the protection, restoration, and sustainable use of terrestrial ecosystems (SDG 15). Blue carbon ecosystems like mangroves and seagrass beds serve as critical nursery grounds and habitats for many ecologically and economically important species, including fish, reptiles, mammals, and birds, and are vital for maintaining biodiversity (Scott and Lindsey, 2022; Fu et al., 2024; Duarte et al., 2013; Macreadie et al., 2021). Integrating blue carbon ecosystems into protected area networks and implementing ecological restoration contribute to achieving Target 15.5, which aims to reduce the degradation of natural habitats.

Beyond climate and biodiversity goals, blue carbon synergizes with other SDGs. Recent studies report that some countries have initiated mangrove restoration or planting programs, and increasing conservation efforts have led to a reduction in human-driven mangrove losses (Goldberg et al., 2020). Over the past decade, the impact of economic growth on mangroves has shifted from negative to contributing to their expansion in area (Hagger et al., 2022). However, an excessive focus on the area might overlook degradation issues, which are difficult to define and monitor over large scales (Carugati et al., 2018).

Furthermore, scenario modelling based on global cooperation indicates that, compared to a business-as-usual scenario, a deep global cooperation scenario could enable coastal nations to sequester an additional 2.96 million tonnes of carbon annually and generate USD 136.34 million in economic benefits by 2030 to some extent (Feng et al., 2023). This would contribute to poverty reduction (SDG 1) and sustainable economic growth (SDG 8). Under deep global cooperation, both developed and developing countries could achieve win-win outcomes: developed countries could scale up mitigation efforts and further assume responsibility for climate change mitigation, while developing countries could enhance their blue carbon resource endowments and improve marine management and technology (Feng et al., 2023), thereby fostering progress towards SDG 17 (partnerships for the goals).

The Ramsar Convention was adopted in 1971 to promote the conservation and sustainable use of wetlands. The Convention adopts a broad definition of wetlands. According to Article 1 of the Convention: “wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres.” (UNESCO, 1994) Article 2, paragraph 1, permits the inclusion of riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands, particularly where these have importance as waterfowl habitat, when designating wetlands for the List of Wetlands of International Importance (UNESCO, 1994). Consequently, wetlands under the Convention encompass all lakes and rivers, underground aquifers, swamps and marshes, wet grasslands, oases, estuaries, tidal flats, mangroves and other coastal areas, coral reefs, and all human-made wetlands such as fish ponds, rice paddies, reservoirs, and salt pans (CI et al., 2010). Accordingly, the Convention applies to blue carbon ecosystems, particularly mangroves and salt marshes. Through its “three pillars” – the principle of wise use of wetlands, the designation of suitable wetlands as Wetlands of International Importance (the “Ramsar List”) and ensuring their effective management, and international cooperation on wetlands – the Convention encourages Contracting Parties to promote wetland conservation and sustainable management within their respective national contexts (UNESCO, 1994).

Successive Conferences of the Parties (COP) to the Convention have repeatedly “noted/recognized” the linkage between wetlands and climate change, providing policy guidance to Contracting Parties through “encouraging/urging” formulations. Resolution X.24, adopted at Changwon (COP 10) in 2008, urged Contracting Parties to manage wetlands wisely to enhance their resilience to climate change and encouraged Parties to take measures to reduce anthropogenic greenhouse gas emissions from wetlands, including peatlands (Ramsar, 2008). Resolution XI.14, adopted at Bucharest (COP 11) in 2012, urged Contracting Parties to maintain and enhance the ecological character of wetlands, including their ecosystem services, to maximize the resilience of wetlands to ecological change driven by climate change (Ramsar, 2012). Resolution XII.11 adopted at Uruguay (COP 12) in 2015 “welcomed” initiatives supporting the conservation and restoration of coastal wetlands (Ramsar, 2015). COP 13 in Dubai (2018) specifically adopted Resolution XIII.14, which focuses on blue carbon ecosystems. This resolution, for the first time within the Ramsar framework, defined blue carbon, stating it is the carbon captured by marine and coastal organisms and stored in biomass, and sediments in coastal ecosystems such as mangroves, salt marshes and seagrass meadows, noting that not all Contracting Parties endorsed this definition (Ramsar, 2018). The resolution reaffirmed the Convention’s purpose of the conservation and wise use of all wetlands and their resources, explicitly including coastal blue carbon and related ecosystems.

As the global blueprint for disaster risk reduction governance, the Sendai Framework identifies unsustainable resource use and ecosystem decline as underlying risk drivers that need to be addressed, specifically promoting an “ecosystem-based approach” and “integrated environmental and natural resource management” as institutional mechanisms (UNDRR, 2015). Although the Framework does not establish a dedicated blue carbon mechanism or clause, it explicitly advocates for ecosystem-based disaster risk reduction in its priority actions. It calls for developing relevant policies and planning for shared resources, such as coastal zones, and for enhancing the sustainable use of ecosystems and integrated environmental and natural resource management to incorporate disaster risk reduction considerations (UNDRR, 2015). Consequently, coastal blue carbon ecosystems, such as mangroves and seagrass beds, receive targeted policy support for their role in disaster risk reduction as natural protective barriers (IPCC, 2022; Cooley et al., 2022). Coral reefs also provide significant coastal protection functions, but are generally not classified as blue carbon ecosystems. The Framework also notes that many disasters are exacerbated by climate change, increasing in frequency and intensity, and severely hindering sustainable development. It states that addressing climate change should be integrated into relevant international processes in a meaningful and coordinated manner, respecting the mandate of the UNFCCC. These arrangements collectively establish a policy foundation for the role of blue carbon-related ecosystems in reducing disaster risk.

Firstly, regarding risk causation and upstream governance, the Sendai Framework identifies unsustainable natural resource use and ecosystem degradation as fundamental drivers of disaster risk, requiring countries to acknowledge and address them. Its “Expected Outcome and Goal” explicitly emphasizes preventing new risks and reducing existing risks through comprehensive and inclusive measures, including environmental measures (UNDRR, 2015). In coastal contexts, protecting and restoring blue carbon ecosystems such as mangroves, seagrass beds, and salt marshes can form part of strategies to mitigate disaster risks like storm surges, erosion, and flooding, particularly in Small Island Developing States (Jones et al, 2020; Blankespoor et al, 2017; Hanson et al, 2011; De Silva et al, 2022). Guided by this approach, the Sendai Framework calls for strengthening the sustainable use and management of ecosystems and implementing integrated environmental and natural resource management approaches that incorporate disaster risk reduction (30(n)); and for promoting the mainstreaming of disaster risk assessment, mapping, and management into rural development planning and the management of mountains, rivers, coastal flood plains, drylands, wetlands, and other areas prone to drought and flooding. Specific measures include identifying safe areas for human settlement while maintaining the protective functions afforded by natural ecosystems (30(g)). This provides a basis for employing measures such as establishing mangrove buffer zones, restricting unplanned development in coastal wetlands, and implementing coastal vegetation restoration as viable policy tools.

Secondly, the Sendai Framework defines four Priority Areas for Action: Priority 1: Understanding disaster risk, by conducting risk assessments and risk mapping that include climate change scenarios; Priority 2: Strengthening disaster risk governance to manage disaster risk; Priority 3: Investing in disaster risk reduction for resilience; and Priority 4: Enhancing disaster preparedness for effective response and to “Build Back Better” in recovery, rehabilitation, and reconstruction. The protection, restoration, and sustainable management of coastal blue carbon ecosystems contribute to advancing all these priority areas (IPBC, 2021). Complementing this, the Sendai Framework paragraph 28(b) calls for promoting collaboration among global and regional mechanisms and institutions to ensure coherence and coordination in the implementation of instruments and tools relevant to disaster risk reduction – such as those concerning climate change, biodiversity, sustainable development, poverty eradication, environment, agriculture, health, food, and nutrition – and to expand such cooperation where appropriate (UNDRR, 2015). This implies that countries should coordinate their actions under relevant frameworks, such as the UNFCCC and CBD, by integrating blue carbon-related measures into their national disaster risk reduction strategies and plans to achieve synergistic, multi-objective policies.

Finally, among the Sendai Framework’s seven global targets, Target (d) – “Substantially reduce disaster damage to critical infrastructure and disruption of basic services, among them health and educational facilities, including through developing their resilience by 2030” – and Target (e) – “Substantially increase the number of countries with national and local disaster risk reduction strategies by 2020” – exhibit relatively high relevance to ecosystem-based resilience building. Although these targets do not explicitly mention blue carbon, integrating ecosystem-based measures into their formulation and implementation can significantly enhance the resilience of critical infrastructure and basic services, thereby improving overall community disaster resilience. Blue carbon ecosystems possess significant carbon sequestration/mitigation functions, delivering ecosystem-based disaster risk reduction benefits. Several assessments have quantified their effects, such as avoided flood damages, as measurable metrics of disaster risk reduction performance (Howard et al., 2017; Narayan et al., 2016; Möller et al., 2014).

A significant challenge in current blue carbon governance is the ambiguity in conceptual definitions and scientific standards (Lovelock and Duarte, 2019). Although international organizations such as the UNEP have proposed a definition for blue carbon, the Intergovernmental Panel on Climate Change (IPCC, 2019) and others note substantial ongoing debate within the scientific and policy communities regarding the specific ecosystem types encompassed by the term (Adame et al., 2024). A consensus is notably lacking on whether to include non-coastal ecosystems within blue carbon (Thoni and Rummukainen, 2025). Unclear definitions result in chaotic governance standards, with significant disparities in the monitoring and accounting standards for blue carbon projects across different countries, thereby reducing the efficiency and sustainability of global blue carbon governance (Macreadie et al., 2021). Concurrently, due to the nascent stage of blue carbon scientific research, evidence and quantification gaps persist. Globally, technical methodologies for developing, verifying, and monitoring blue carbon projects and their impacts on Sustainable Development Goals are still under development (Chalastani et al., 2022; Levin, 2021).

The issue of blue carbon is embedded in a fragmented manner across different international processes, including the UNFCCC, CBD, the Ramsar Convention, SDGs, and the Sendai Framework. These mechanisms differ in their objective hierarchies, measurement indicators, mandatory/voluntary nature, implementation pathways, and resource preferences. Both horizontal coordination (e.g., climate-biodiversity-wetlands-disaster risk reduction) and vertical alignment (e.g., global rules-national strategies-local implementation) require significant strengthening (Wylie et al., 2016). A common consequence is that a single coastal wetland restoration project often must simultaneously comply with multiple requirements for carbon accounting, ecological integrity, land use and tenure, and disaster risk reduction and adaptation. The lack of unified “minimum consistency” standards and streamlined processes increases governance costs and dilutes policy effectiveness.

Blue carbon resources are highly concentrated in developing coastal nations and Small Island Developing States, which often lack sufficient funding, technology, and data capacity (Seddon et al., 2020). The Common But Differentiated Responsibilities (CBDR) principle is a crucial tool for addressing equity in international environmental governance. However, its implementation in blue carbon governance faces significant challenges, manifested practically as: high project preparation and Monitoring, Reporting, and Verification (MRV) costs (Forest Trends’ Ecosystem Marketplace, 2024); limited direct access to financing; insufficient technological localization (IPCC, 2014); and the need to strengthen community participation and rights protection. The resulting mismatch between “capacity-responsibilities-benefits” not only affects the quality of blue carbon projects but also undermines the sustainability and social legitimacy of long-term governance (Forest Trends’ Ecosystem Marketplace, 2024). Furthermore, capital-dominated carbon trading, characterized by elements of “carbon colonialism”, exacerbates the governance imbalance between the Global North and South (Dehm, 2016).

Blue carbon projects typically face high upfront costs, and carbon measurement and monitoring are often costly and labor-intensive. The timing of credit generation is uncertain, which affects the pace of revenue realization (Friess et al., 2022). Current funding for Nature-based Solutions (NbS), including blue carbon, comes predominantly from public sources (approximately 82%), representing a severe overall underfunding. Private capital constitutes a small share and is channeled through fragmented sources, making it difficult to form a continuous and stable supply (Rizvi et al., 2015). In practice, funding sources are fragmented and suffer from maturity mismatches. Projects often lack stable support spanning from feasibility studies and baseline/reference setting to monitoring networks and long-term maintenance. There is a scarcity of directly accessible, ‘small-scale, rapid, and replicable’ funding windows, which are crucial for supporting the numerous community-scale and local government-led restoration projects (WEF, 2025). Furthermore, the lack of standardized statistical accounting and performance indicators hinders the ability of different funders to establish consensus for blended finance or results-based payment schemes, creating both confusion and an enormous barrier to creating a stable, trusted market for blue carbon credits (Macreadie et al., 2022).

Unified definitions and accounting standards would enhance global governance consistency and credibility, avoiding contradictions and conflicts during policy implementation (Macreadie et al., 2021; IOC/UNESCO et al., 2011). It is recommended that, under the UN-Oceans framework, relevant UNFCCC technical bodies, the IPCC, the CBD Secretariat, FAO, UNESCO-IOC, and others jointly lead the development of a “minimum consistency standards package” for coastal blue carbon ecosystems. This package should standardize: project typologies and boundary definitions; baseline establishment and additionality determination; leakage and risk mitigation; handling of permanence and reversals; monitoring variables and sampling frequencies; and data openness and verification procedures. This standards package would not replace the existing rules of individual mechanisms. However it would provide a “common layer” for cross-regime mutual recognition and linkage, thereby reducing implementation costs and enhancing transparency.

Using “Integrated National Blue Carbon Policy Packages” as a lever, promote the alignment of objectives and mutual recognition of indicators between NDCs, NBSAPs, Ramsar Site management plans, and national disaster risk reduction strategies (Sendai). Relevant policies may include: (1) Designating coastal ecological buffer zones in territorial and marine spatial planning; (2) Integrating blue carbon restoration into NDCs/Adaptation Communications, with simultaneous registration and monitoring within NBSAPs/wetland management plans; (3) Incorporating “Ecosystem-based Adaptation/Ecosystem-based Disaster Risk Reduction (EbA/eco-DRR)” into local contingency plans and investment portfolios, establishing long-term maintenance mechanisms co-financed by fiscal budgets and climate finance; (4) Strengthening two-way interaction mechanisms between global goals and local practices, facilitating the translation of global governance experience to the local level and the promotion of local experience globally.

The institutional rigidity of the Common But Differentiated Responsibilities (CBDR) principle should be reinforced within the UN system, with explicit definitions of the ecological debt compensation obligations of developed countries. Calculations could employ the AOSIS proposal based on “cumulative emissions from 1850–2025 multiplied by ecological loss”. Mechanisms for funding and technology transfer specific to blue carbon governance must be operationalized to ensure effective implementation. This involves establishing mandatory funding fulfillment mechanisms, creating a dedicated UN blue carbon fund with direct disbursement channels to communities, and refining the legal framework for ecological debt compensation to ensure developing countries receive adequate and stable financial support. Furthermore, the risks of “carbon colonialism” must be mitigated by actively promoting the protection and utilization of developing countries’ rights to govern their own ecological resources (Dehm, 2016).