Despite being fundamental to any management of BCE, accurate and comprehensive data on distribution, condition and carbon fluxes remain uneven across the region. The extent of seagrass meadows in particular is often underrepresented in national inventories and international reporting mechanisms (Lee et al., 2025). Whilst the ability to map seagrass remotely has advanced in recent years, the mapping of underwater ecosystems remains challenging (Veettil, 2020).

Carbon stocks in BCE are highly variable due to the influence of multiple biological, chemical and physical factors and their interacting effects (Williamson and Gattuso, 2022). Increased data on the sources of sediment to BCE, the carbon within the sediment and how this might change over time due to LULCC are required. A recent review of blue carbon studies in the Philippines (Corcino et al., 2023) concluded that more research and sustained monitoring of BCE, particularly seagrass meadows, is required. Seagrass meadows have a 76-fold range between the highest and lowest reported carbon burial rates (Williamson and Gattuso, 2022), additionally in many seagrass beds, around 50% of the organic carbon is from non-seagrass sources (Oreska et al., 2018). This information is vital to carbon crediting as carbon from external sources cannot be credited despite large inputs of allochthonous carbon to BCE.

There is uncertainty around how long BCE take to recover following disturbance and similarly, although there is measurement of changes in various carbon pools (biomass, sediment and dead organic matter), over time since regeneration (Azman et al., 2023) studies do not yet include measurement of gas emissions. There is a need for better understanding of methane and nitrous oxide release due to land use change impacts and before, during and after any restoration as the impact of LULCC on sediment carbon and nitrogen dynamics is still unclear (Tan et al., 2022).

Addressing these gaps requires deployment of technologies, such as high-resolution satellite remote sensing and drones (Fakhrurrozi et al., 2023), alongside in situ measurement, use of geospatial information systems (GIS) and modelling. Machine learning can be used with data obtained from satellites and drones to automate and improve extent mapping and carbon stock quantification (Pham et al., 2023). These technologies should be deployed alongside capacity-building efforts to train local actors in data collection and interpretation. Regional data-sharing platforms and open-access geospatial databases could enhance transparency, facilitate collaboration and reduce duplication of efforts.

The disconnect between science, policy and practice has been identified as the most important driver of BCE decline in SEA (Fortes, 2018a). Policymakers may lack the technical capacity or institutional mandates to engage with emerging findings, while researchers may not produce outputs that are readily usable in decision-making contexts (Fortes, 2018a). Many SEA countries, including Indonesia, Malaysia and Philippines (Thu Thuy and Thanh Thuy, 2019) are exploring BCE as a strategy in their Nationally Determined Contributions (NDCs) under the Paris Agreement. It is therefore important that the knowledge gap is bridged to implement science-based policies that ensure reliable carbon storage and align with local socio-economic priorities.

Strengthening science-policy interfaces through the establishment of boundary organisations, policy fellowships and co-production mechanisms is essential. Promoting joint forums where scientists, policymakers and community representatives can regularly interact will enhance mutual understanding, help align research agendas with policy priorities and have the potential to increase conservation success (Aswani et al., 2012). Additionally, embedding scientific advisors within government agencies and offering incentives for applied research can help bridge the divide.

The process of adaptive management is intended to overcome the necessity for decision makers to act with limited or incomplete information. Adaptive management frameworks are responsive, with built-in flexibility, monitoring and review, and should adjust to socio-economic change, such as urbanisation or increased tourism, and climate impacts as well as improved knowledge.

Many conservation and restoration efforts operate at local scales yet are affected by regional or global drivers such as upstream deforestation, industrial expansion and international trade. Conversely, national and regional policies may not reflect the ecological heterogeneity and socio-cultural diversity of local BCE contexts. Conservation initiatives, particularly those driven by international donors and Non-Governmental Organisations (NGOs), often prioritise regional or global agendas over local needs. There may be issues around increased monitoring and regulation of marine space, which are seen to exclude local interests and constrain access (Clifton and Foale, 2017). Protecting and restoring BCE as wetlands should ensure multiple benefits are delivered (Canning et al., 2021), but community support is vital to project success (Yusri et al., 2019).

The interconnectivity of BCE and associated marine ecosystems, such as coral reefs and kelp forests is sometimes overlooked as connections can be difficult to manage due to jurisdictional issues (Howard et al., 2017). A change of perspective is required, which considers BCE as components of a larger interdependent system (the LOAC). This is vital to ensuring their continued provision of ecosystem services and maintaining their role in carbon cycling and storage. There is a need for new frameworks to identify, quantify and integrate the ecological and biogeochemical interlinkages between the land and BCE; between the various BCE; and between coastal systems and pathways to carbon storage in the open ocean.

To address this, governance arrangements must support nested approaches where interventions are aligned across multiple levels. Local knowledge systems, customary practices and Indigenous governance structures must be integrated into broader planning frameworks to ensure that interventions are contextually grounded and socially legitimate. The success of blue carbon conservation hinges on the active participation of local communities in decision-making processes and empowering local communities to adopt sustainable practices ensures conservation efforts align with their socio-economic interests, for example by safeguarding livelihoods or creating alternative income streams. A systems approach could be implemented that considers the dynamics between coastal societies and ecosystems as part of interconnected social-ecological systems and links to global processes, whilst simultaneously taking into consideration the rights and needs of local communities.

Whilst voluntary carbon markets offer an opportunity to mobilise private sector funding for blue carbon projects, they alone are unlikely to provide adequate finance, particularly where they fail to integrate broader socio-ecological values, risks and consideration of upstream LULCC impacts (Friess et al., 2022; Howard et al., 2023; Macreadie et al., 2022).

Carbon standards such as the two major, internationally accepted methodologies, the Verified Carbon Standard (Verra) and Plan Vivo (Claes et al., 2022), used to certify projects and facilitate trading are necessarily stringent, making them expensive and difficult to achieve (Wylie et al., 2016). They are also hindered by regulatory and legal uncertainties (Mack et al., 2022; Vanderklift et al., 2019). High transaction costs and complexity of the certification processes can exclude small-scale or community-led projects (Dencer-Brown et al., 2022), whilst volatility in carbon prices and lack of standardised metrics undermine confidence among investors and stakeholders (Vanderklift et al., 2019). It is also acknowledged that there is often a key gap in the integration and application of indigenous and local knowledge in the implementation of blue carbon projects (Macreadie et al., 2022).

A potential solution is to look beyond carbon and incorporate the multiple benefit streams (such as coastal protection, fisheries productivity and cultural heritage) provided by BCE in a form of payment for ecosystem services (PES) (Rakotomahazo et al., 2023; Shilland et al., 2021), which has been effective in protecting and restoring other ecosystems (Charoud et al., 2023).

Maritime SEA comprises 10 countries with varied demographic and economic characteristics. Coastal governance involves a complex network of formal and informal institutions operating across multiple scales (Steenbergen et al., 2019). State governance of BCE is frequently spread across multiple agencies (e.g. environment, fisheries, forestry, planning) each with distinct mandates and limited coordination. To address the complex, interconnected and transboundary issues impacting BCE in a region that has historical been governed through a complex mix of formal, informal, religious and customary law, requires a holistic transboundary governance approach. This necessitates that policies are coherent across economic sectors and levels of governance to achieve balance between preserving ecosystems and meeting the socio-economic needs (access to food and water, health and livelihoods) of their populations. Collaborative efforts among SEA nations, NGOs and international bodies have led to progress in promoting the protection of BCE, for example the Oceanus Conservation Mangrove Restoration Project in the Philippines and the International Climate Initiative (IKI) Seagrass Ecosystem Services Project, which operates over five SEA countries (Miller and Taylor, 2024). Building effective coordination requires institutional reforms, such as establishing inter-ministerial task forces, harmonising policy instruments and developing shared implementation roadmaps. Progress is often slow, as previously noted by PEMSEA members in the Changwon Declaration of 2012, in which they committed to renewing their efforts (Gonzales et al., 2019). Cross-sectoral leadership and political will are critical to advancing coherent, adaptive and forward-looking BCE governance.

A robust evidence base is essential for effective BCE protection, restoration and management. Recent studies describe best practice in data collection (Dahl et al., 2025) and highlight the potential for the use of remote sensing in the monitoring, reporting and validation (MRV) of BCE (Malerba et al., 2023). Baseline mapping of extent and condition of BCE should be carried out at national and regional scales, for use in accounting and biodiversity monitoring. Regionally coordinated monitoring frameworks should be developed to track ecosystem health, habitat extent, carbon fluxes and socio-economic benefits, such as impacts on health, education and economic living standards. This would monitor success, assist in understanding the effect of climate change and other anthropogenic impacts, such as LULCC, on these ecosystems and inform future policy and management. Standardised protocols for measuring sediment carbon stock, sequestration rates, gas emissions and connectivity across BCE types will improve consistency and comparability (Williamson and Gattuso, 2022). Open-access platforms, such as regional blue carbon observatories, could enhance data accessibility and foster collaboration among governments, NGOs, academia and local communities. Integrating local ecological knowledge and citizen science initiatives will also enrich monitoring efforts and promote local ownership. All of this will go some way towards closing the data gap and could in the long-term reduce the effort and costs for individual projects.

Science, policy and local knowledge must be brought into closer alignment through transdisciplinary collaboration and inclusive governance to bridge knowledge gaps and ensure science-based policies are aligned with local socio-economic needs. The science must be relevant, so that in addition to providing data, it can present ideas that can enhance policy. The alignment of scientific research with policy to support MRV will also increase the uptake of blue carbon projects.

Those who are directly reliant on BCE are most vulnerable to degradation and are most likely to be impacted by protection and restoration measures. Codesign, community-based monitoring, participatory planning processes and co-management arrangements can help bridge epistemological divides and ensure legitimacy. An understanding of the local governance context is vital to projects being constrained by socially and politically charged situations (Thomas, 2016). Policies should mandate community representation in decision-making bodies, while also creating enabling environments for grassroots innovation. Tools such as participatory mapping, scenario building and benefit-sharing agreements can facilitate more equitable and durable conservation outcomes. To build trust and accountability, accessible feedback mechanisms and dispute resolution channels should also be institutionalised.

Effective BCE governance must reflect the spatial and functional interconnectivity of ecosystems, in addition to addressing global problems whilst maintaining a local focus. Combinatory theories of governance, such as adaptive management have evolved because singular theoretical perspectives are not well suited to understanding and addressing the multiple factors influencing environmental governance (Partelow et al., 2020). Governance approaches that recognise the complex spatial and temporal relationships in the LOAC offer a holistic framework to integrate ecological, hydrological and socio-economic dimensions. Nested governance models, linking local user groups to municipal, national and regional authorities, are needed to coordinate interventions and overcome the issue of terrestrial and aquatic environments coming under the jurisdiction of different authorities. Cross-boundary planning tools, such as marine spatial planning (MSP), should be expanded to incorporate upstream-downstream linkages and cumulative impacts. Scenario planning and adaptive management frameworks will be critical in dealing with uncertainty and responding to shifting climate and development pressures.

Given that SEA encompasses multiple countries with shared marine ecosystems and mutual threats, regional cooperation is essential. Collaboration across borders and jurisdictions is vital to understanding BCE interconnectivity and the implementation of effective restoration and protection. Institutions like ASEAN, PEMSEA and the Coral Triangle Initiative provide platforms for harmonising policies, pooling resources and scaling best practices. In addition to recent calls for co-operation on blue carbon between China and countries of SEA at bi-lateral, sub-regional and trans-regional levels (Zhang, 2025), it has previously been proposed (Fortes, 2018b) that existing regional initiatives should come together to adopt a multi-regional approach to nature-based climate mitigation entitled “The Blue Carbon Triangle”. This could serve as a collaborative initiative for joint monitoring, restoration and capacity building across key BCE-rich countries. Regional centres of excellence, exchange programs and joint training initiatives could foster a common knowledge base and enhance trust among stakeholders. Formalising data sharing agreements and legal instruments for cross-border conservation could further strengthen transboundary coherence.

A major challenge in protection and restoration of BCE is the need for sufficient finance (Friess et al., 2022). Schemes must be economically viable and yield greater returns as BCE than other potential uses (e.g. conversion to agriculture). Sustainable financing must reflect the multi-dimensional value of BCE. Beyond carbon credits, innovative mechanisms such as biodiversity offsets, blue bonds, climate adaptation finance and insurance-linked instruments should be explored. Blended finance models, combining public, private and philanthropic capital, could help de-risk investments and increase scalability.

Financialising ecosystem services in addition to carbon sequestration can be achieved under PES schemes, which should be designed with robust safeguards to ensure equity, transparency and long-term viability. A study into the viability of PES schemes in the Philippines concluded there were governance and implementation challenges due to the complexities of the coastal zone, but that PES had the potential to overcome these (Thompson et al., 2017). Establishing investment guidelines and Common Asset Trust (CAT) through a set of agreements and polycentrically governed institutions would safeguard BCE as common property by effectively linking finance and governance (Costanza et al., 2021). Aligning these mechanisms with local development goals will enhance synergies and reduce trade-offs between conservation and livelihoods.

Taken together, these strategies offer a roadmap for system-based BCE governance that integrates science, equity and resilience at its core. Building the institutional, financial and social foundations for such a transition will require persistent effort, political leadership and broad-based coalitions across sectors and scales.