Blue Marine Foundation – Written evidence (NSD0023)



Blue Marine Foundation (BLUE) welcomes the Committee’s inquiry into the role that nature-based solutions can play in delivering the government’s target of net zero carbon emissions by 2050. BLUE is a UK based marine conservation charity that works on both policy reform and delivers on the ground projects around the world. Our projects range from restoring heavily depleted oyster reefs in the Solent and Essex to working with partners in the Maldives to improve the conservation of vulnerable sharks. From a policy perspective we work on ending overfishing in UK waters and on improving sustainable management of and habitat protection and Regional Fisheries Management Organisations (RFMOs). In light of the increasingly clear scientific consensus of the importance of the ocean to mitigating and adapting to climate change BLUE has taken significant interest in so called ‘blue carbon’.


We have provided responses to specific questions that we feel we are well placed to answer but we would like to highlight two especially important themes that run though our evidence and that have become apparent through our projects. Firstly, the legal and legislative frameworks and regulations for developing nature-based solutions are, in large part, already in existence. While there are issues around financial mechanisms it is often a lack of political will to implement the necessary solutions to the twin crises of biodiversity and the climate, and specifically where nature-based solutions can be effective in tackling both, is as much of a barrier as funding. Secondly, we would like to strongly emphasise that nature-based solutions are exceptionally effective because of the ‘co-benefits’ that accrue from effective marine protection and habitat recovery. Restoring the marine environment will increase the ocean’s ability to mitigate climate change by increasing its capacity to sequester carbon; will increase resilience against the impacts of climate change resulting in not only in the improved health of the marine environment but more economically viable and sustainable fisheries; and will enable widespread recovery of species and populations that are currently under severe pressure from human activity.


When discussing the marine environment in the context of climate change it is important to note that the ocean has absorbed one-third of human-related CO2 emissions (Sabine et al., 2004; Gruber et al., 2019) and while the sea is threatened by climate change, it also provides many solutions to the climate crisis (Hoegh-Guldberg et al., 2019). The protection of ‘blue carbon’ habitats is one of these solutions.


  1. What is the potential scale of the contribution that nature-based solutions can make to decarbonisation in the UK?


Which ecosystems are most relevant to the UK for nature-based solutions, and which have the largest potential to sequester carbon or reduce emissions?


Nature-based solutions have the potential to contribute significantly to the UK’s decarbonisation targets. However, the extent of the contribution is down to political choice – the more of the marine environment that is protected from harmful activities, and the more that fisheries in particular is shifted towards less damaging methods, then the greater the contribution nature-based solutions can make.


Not all ecosystems are of equal value from a carbon sequestration perspective. Seagrasses, mangroves and saltmarshes are widely recognised as the habitats with the greatest capacity for carbon sequestration and storage. While the UK does not have mangroves our seas and coasts have great potential for recovery of saltmarsh and seagrass. Furthermore, there is increasing evidence[1] that the seabed itself provides significant carbon storage and that human activity, notably demersal trawling and dredging, releases substantial carbon.


The protection and restoration of marine habitats has the potential to contribute significantly to the UK’s decarbonisation efforts. Blue carbon habitats are prime examples of nature-based solutions to climate change, providing both mitigation and adaptation benefits. The habitats that are currently most recognised for their carbon storage potential includes saltmarsh (tidal marsh), seagrass and mangroves. However, other habitats, including those within UK waters, are being increasingly recognised for their climate mitigation capabilities, including seabed sediments, reefs and kelp forests.


Conservation of, and investment in blue carbon habitats presents two policy actions: protection and restoration. Protection concerns keeping the substantial carbon stored within these sites remains sequestered away. Restoration concerns restoring important carbon sequestration habitats to further enhance the marine environment’s capacity to sequester atmospheric CO2 and long-term carbon burial. The UK’s Exclusive Economic Zone (EEZ) covers 757,000 square kilometres providing a huge area for potential carbon mitigation.


To our knowledge there are no total UK estimates accounting for all blue carbon components. Scotland and Wales have individually produced initial estimates for blue carbon stocks. In Scotland, the marine environment is estimated to store 9,636 million tonnes of CO2e (Burrows et al., 2017). In Wales, it is estimated that marine habitats sequester at least 26,100 tonnes of carbon every year, with saltmarshes and intertidal flats accounting for a large percentage (Armstrong et al., 2020). This represents around 7 per cent of the amount sequestered by Welsh forests every year (Armstrong et al., 2020).


Perhaps the most striking aspect of marine nature-based solutions to climate change is the enormous co-benefits that these solutions provide. By implementing marine protected areas that deliver protection from human activity the UK would not only significantly increase its capacity to reach its carbon goals but go a long way to meeting the biodiversity targets that, to date, we are notably failing to meet. Marine protected areas (MPAs) have been demonstrated to dramatically increase abundance of important commercial species, provide a haven for non-commercial species, and allow for ecosystem recovery. The costs of fully protected marine areas are likely significantly lower (and can, in many instances, be a net economic benefit) than policy options with a similar impact on land – MPAs provide the ‘spillover effect’ benefiting commercial fisheries in surrounding areas and protect important spawning and nursery sites.


  1. What major scientific uncertainties persist in understanding the effects of nature-based solutions and affect their inclusion in carbon accounting, and how can these uncertainties be addressed?


There is a significant amount of existing research and evidence that underpins the science of blue carbon as a nature-based solution to climate change. The fundamental concepts strongly justify why we must protect and restore these habitats, with blue carbon science already underpinning numerous projects around the world (Macreadie et al., 2019).


Some habitats, such as seabed sediment and macroalgae, present significant opportunities for further research as the level of carbon sequestration provided by these habitats is, as yet, less clear. Examples of areas where more research is needed include the rates of carbon assimilation and the certainty of long-term fixed carbon storage (Howard et al., 2017; Pessarrodona et al., 2018; Lovelock and Duarte, 2019).


While uncertainties exist around the role of carbon storage within shellfish beds, research is exploring how they may increase carbon sequestration and storage capacity in other habitats, thus providing an indirect mitigation potential (Ridge et al., 2017). Here, salt marsh fringing oyster reefs have been shown to preserve carbon-rich marsh sediment from eroding and facilitated seaward migration of salt marshes (Ridge et al., 2017). More novel concepts, such as ‘fish carbon’, have uncertainties around long-term sequestration values and how this could be considered within fishery carbon budgets (Howard et al., 2017) provide further justification for the adoption of the precautionary approach to fisheries management.


For other habitats that are already recognised within national accounting and by the voluntary market, such as tidal marshes and seagrass, further research around historical losses, current distribution and improved spatial data would help support the development of future carbon projects.


How reliable are the estimates of the quantity of greenhouse gas emissions reduction or sequestration by nature-based solutions, as well as the duration and reliability of storage?


Carbon incorporated into plant biomass is stored for decades or centuries at most (Chambers et al., 2001; McLeod et al., 2011), whereas carbon in the soil or seabed can accumulate over hundreds or thousands of years and be locked away for millennia (Chmura et al., 2003; Duarte, Middelburg and Caraco, 2005; Lo Iocano et al., 2008). This fact, that seabed carbon storage is often occurs over extremely long time frames, presents a double risk posed by destructive fishing techniques. Not only do these techniques, damage the seabed’s ability to sequester carbon by destroying habitats but also releases the carbon that has accumulated. Like their terrestrial counterparts, marine ecosystems are extremely vulnerable to the impacts of climate change – this should act as an impetus to rapidly protect and restore these habitats, which will equally improve their capacity to continue mitigating climate change.


  1. Are there good examples of nature-based solutions already being undertaken in the UK or elsewhere, and what can we learn from them? 


There are numerous examples from around the world, including the UK, of nature-based solutions in the marine environment. It is important to note that whilst many of these projects involveactive restoration’ (such as the planting of seagrass or the restoration of oyster reefs) that many projects require no, or very little, active work – they simply need to be protected from the activities (such as fishing, pollution or aggregate dredging) that were damaging them. This lesson is a key one that should be learnt – that in many instances nature will recover on its own.


A recent report by The Marine Conservation Society and Rewilding Britain (2021) details various UK case studies specific to blue carbon, including the coastal wetland restoration of the Steart Marshes in Somerset; a seagrass restoration project in Pembrokshire, Wales; and the recovery of the Lamlash Bay No Take Zone (NTZ), Isle of Arran, which has an estimated carbon stock of 8,046 tonnes/km.


Several examples of successful seagrass restoration projects also exist, achieved via removal of environmental stressors, such as water pollution (de los Santos et al., 2019) large-scale seeding programs (Orth et al., 2020) and the introduction of marine protected areas and legislation (Diaz-Almela, E. & Duarte, 2008). For example, a very successful project in Virginia, USA, restored 3,612 hectares of eelgrass (Zostera marina) in two decades, dispersing 70 million seeds in an area where eelgrass was eradicated 70 years previously by a slime mold disease (Orth et al., 2020).


There are numerous nature-based solutions operating or in development around the world. For example, Kenya is home to a community-led mangrove conservation and restoration initiative. Conservation International has also invested in a large-scale mangrove restoration project in Colombia, which will provide essential coastal protection to local communities and sequester significant amounts of carbon. With many more blue carbon projects applying for certification under voluntary standards (for example the Verified Carbon Standard), key lessons learned is the vital importance of community involvement; ensuring the community benefits directly from the project; and continued, rigorous monitoring of co-benefits (including carbon sequestration over time).


  1. How should implementation of nature-based solutions be integrated with other government policies for landscapes and seascapes, for example, agricultural, forestry, and land-use planning policies?


Blue carbon projects have the capacity to contribute to the fulfilment of government policies and treaty obligations on biodiversity. For example, the delivery of genuinely protected MPAs would contribute to UN SDG14, Convention on Biodiversity targets and the requirements under the Marine Strategy Framework Directive (MSFD). It is important to note that the UK has failed to meet its objectives under these obligations to date, often buy significant margins. Protection and restoration of blue carbon habitats would enhance biodiversity, support fisheries, and could increase eco-tourism revenues. For example, despite covering less than two per cent of the Mediterranean Sea, seagrass supports at least a third of the total value of commercial species landed within the region (Jackson et al., 2015). Seagrass and other blue carbon habitats also offer vital coastline protection from natural disasters, extreme weather events and erosion, provide raw materials, and enhance pollution mitigation and water purification (Cohen-Shacham et al., 2016).


Policy integration is preferable to a disjointed approach but integration, in and of itself, isn’t a panacea when the primary barrier to progress on biodiversity is the continuation of short-term decision making. The MSFD provides a good example of where policy integration was implemented but, as this did not change decisions, then it simply led to a ‘coordinated failure’ of policy.



Marine and coastal nature-based solutions have significant potential to contribute to the UK’s efforts to decarbonise. However, BLUE would caution against the idea that these efforts should be in place of efforts to reduce emissions from other activities. Furthermore, we would strongly emphasise that habitat protection, restoration of fish stocks and the recovery of species that have seen their abundance decline should be considered valuable goals in their own right. The government should urgently prioritise ending overfishing, properly implementing protections in the MPA network and transitioning the UK’s fishing fleet towards far less damaging fishing methods. Blue Marine Foundation would like to thank the Committee for launching this inquiry and we would welcome the opportunity to discuss these issues in further detail.


10 September 2021