PHOTO: Mohamed Sameeh

THE STATE OF BLUE CARBON RESEARCH

Our ocean deeply influences the global carbon cycle through coastal blue carbon (mangroves, seagrasses, macroalgae and salt marshes) and oceanic blue carbon (phytoplankton, marine animals, and other open ocean biota) mechanisms. It has been 10 years since the term “blue carbon” was coined (2009) and although the importance of these ecosystems and mechanisms is not yet entirely understood, many of the conclusions posited in the first blue carbon published research have been continually affirmed and refined including the following:

• Whereas open ocean surface phytoplankton capture carbon from the atmosphere via photosynthesis, only a relatively small but important fraction of that carbon sinks all the way to the deep sea floor without being respired back to the atmosphere. Geoengineering schemes to stimulate phytoplankton growth and carbon burial are still burdened with controversy, uncertain outcomes and efficacy.

• Key coastal ecosystems (mangroves, seagrass meadows and salt marshes) have outsized carbon burial rates compared to terrestrial ecosystems with important long-term carbon storage potential.

• These coastal ecosystems also provide significant co-benefits to coastal communities including mitigating impacts of sea level rise and extreme storms while providing diverse goods and services.

• These key ecosystems are endangered and urgently threatened by pollution run-off from land, urban development, aquaculture and overfishing. When disturbed these ecosystems emit stored carbon and lose their capacity to sequester carbon.

• Despite being critically important to biodiversity and coastal community food security, coral reefs do not act as carbon sinks, but in fact are modest carbon sources due to the chemistry of their growth.

Over the last decade research published in hundreds of papers has revealed some new key insights relevant to our collective understanding of and partnership with blue carbon ecosystems including the following:

• Emergent techniques of local community-led conservation and restoration of the key blue carbon ecosystems (especially mangroves) can preserve and enhance coastal community food security and material economy while creating or maintaining carbon capture and coastal protection benefits.

• Formerly thought of as modest stores of labile carbon (easily consumed by other organisms and thus respired back to the atmosphere), macroalgae (kelp bed) ecosystems are increasingly recognized as critical contributors to long term blue carbon capture.

• Ocean farming techniques to create or reforest macroalgae ecosystems have emerged with carbon mitigation and sequestration potential.

• The mechanisms by which marine vertebrates (fish, whales, etc.) impact oceanic blue carbon capture and deposition have been identified and begun to be measured.  Whales, in particular, appear to play an outsized role in stimulating the productivity and sink capacity of open ocean phytoplankton.

• While still not totally known, the extent of existing and potential seagrass meadow ecosystems has been assessed as much larger than earlier thought pointing to significant carbon capture potential as emergent lower cost techniques for establishment and restoration are tested and developed.

• While potentially controversial, novel blue carbon ecosystems can be created in certain places where drawing in seawater to arid inland regions can create significant carbon capture processes and food security benefits or in the open ocean where artificial macroalgae ‘reefs’ are proposed.

There still exists a “charisma” gap for blue carbon. Whereas the loss of terrestrial rain forests has captured popular attention, the world is losing its coastal habitats four times faster. Action is being taken, but needs to be scaled to match the magnitude of the crisis.

Planktonic algae in open ocean also plays a role in the global carbon sequestration cycle, sequestering 9.9 Pg C/yr via photosynthesis, of which 0.14Pg C/yr ends up in deep ocean sediment carbon stocks (Spalding, 2016)[15].

A number of mechanisms influence the biological pump that humans may potentially in turn influence through our behavior and disturbance.

A simplified analysis was done to measure the relative reportive impact of these mechanisms (where C sequestration potential data was reported by Grid Arendal.

When considered with current understanding, Coastal Blue Carbon ecosystems and associated Blue Carbon mechanisms are the priority focus.  Coastal Blue Carbon ecosystems influence Oceanic Blue Carbon mechanisms by stimulating the biological pump as critical breeding habitat for marine vertebrates (fish, turtles, etc.) who play a role in the biological pump (see, for example, this article on impact of fish stocks).  

CO-BENEFITS OF COASTAL BLUE CARBON

Similar to how tree-planting campaigns can have adverse impacts when conducted without local community control and skillful ecological oversight, so too can Blue Carbon initiatives. The Blue Forests Project has developed a Blue Carbon Code of Conduct which prioritizes community decision-making, agency of indigenous communities and protecting human rights. The code recommends adopting a lean, cost-effective and iterative approach that prioritizes learning from on-the-ground results and pilot projects rather than drawn-out and costly planning processes. Thus, when blue carbon projects are executed effectively and comprehensively co-benefits can be achieved including coastal protection from extreme weather events, improved sea level rise adaptation, pollution mitigation/ nitrogen cycling, jobs & co-products and increased Fish Stocks, oxygenation of coastal waters, nurseries for helping to restore world fish stocks.

FUNDING BLUE CARBON

Blue Carbon projects (conservation, restoration or other) appear to receive a minority of global philanthropic funding associated with the one world ocean and ocean environments. FundingtheOcean.org (Foundation Maps by Candid) lists $8.3 Billion total dollar value from 51,412 global grants towards the ocean from 2009-2019. The number of of global grants to Blue Carbon related initiatives from 2009–2019 totaled 175 (0.34% of total grants toward the ocean) for $20,000,000 total (0.24% of total giving toward the ocean).

A separate analysis of data provided by CEA Consulting showed 317 grants from 2004–2017 broadly classifiable as Blue Carbon initiative support for $57,395,198 total.

Some patterns appear to be clear:

• A small percentage of philanthropic funding for oceans and ocean health has been allocated to Blue Carbon initiatives or projects identified as Blue Carbon related

• Mangroves receive the majority of Blue Carbon funding

Not including conservation costs (creating MPAs, etc.) but only considering active restoration and creation of certain Blue Carbon ecosystems shows a need for between $425 Billion to $60 Trillion (USD) to achieve total potential impact. This cursory analysis also points to some critical needs for funding to reduce the average cost of restoration and creation and to better understand how natural (not active) revegetation might occur from protection and conservation (to reduce the total cost). Current philanthropic giving needs to be catalytic to larger pools of resources as the total philanthropic given to oceans is a couple of orders of magnitude too little to fully resource Blue Carbon Ecosystem restoration and protection.

Not all potential blue carbon ecosystem improvements are self-evidently ready for action for enhancing carbon capture and ecosystem health. This is not to say that all potential blue carbon ecosystem improvement initiatives are not worthy of attention and action, but not all share the same degree of readiness for acceleration of carbon capture and storage. 

Lovelock, et al., provide the best and most up to date analysis of readiness to be considered “actionable” blue carbon ecosystem initiatives. The analysis demonstrates a bias for action in coastal environments—seagrass, mangrove, tidal marsh, and macroalgae ecosystems.

The series of interviews accompanying this report as well as the literature point towards specific key blue carbon ecosystems and specific mechanisms and techniques as potentially providing the highest leverage for rapid acceleration and greatest beneficial impact. These include:

MANGROVES

Not all mangrove typologies have the same restoration capacity or priority for ecosystem improvement initiatives. Some research indicates that overall, mangroves in deltaic coasts such as the Mississippi River delta, the Amazon in Brazil and the Sundarbans in India and Bangladesh can sequester more carbon yearly than any other aquatic or terrestrial ecosystem on the globe. These can be considered the world’s blue carbon hot spots.

That said, others have assessed, in detail, particular regions in the world where mangrove restoration is most feasible for greatest carbon impact over the greatest area[20].  The most recently provided estimate of total global area of mangroves is 136,714 km2, based on 2016 data. Almost 90% of the world’s restorable mangroves are located in 24 countries. Addressing the top five countries alone would include 56.5% of mangroves that can be restored.  

SEAGRASS

Seagrasses are common and form meadows in coastal environments, typically in very shallow waters down to 60 m depth. They occur in many areas of the world, but mainly in tropical Atlantic and tropical Indo-Pacific waters.

Some 30% of seagrass ecosystems have been lost globally over the last 50 years.

Seagrass and Carbon: The Stats

• Globally, seagrass ecosystems could store as much as 19.9 Pg/C

• The current seagrass carbon pool lies between 4.2 and 8.4 Pg/C[24]

• When healthy and not overgrazed, seagrass soils have the potential to sequester 1.38 Mg C/ha per year.

Priority Locations

For seagrasses, factors that affect carbon sequestration include water depth, turbidity, and other habitat variables. Priority for conservation and restoration should be given to large persistent species in shallow/low turbidity areas. Areas where coastal fishing communities can perform the active restoration and/or engage in co-managed conservation should be prioritized.  Countries with active efforts include Madagascar, Malaysia, Indonesia, Mozambique, Solomon Islands, Sri Lanka, Vanuatu and Abu Dhabi.

It should be noted that in the case of restoration, a time lag of 10–20 years might be required to achieve carbon accumulation rates comparable with natural seagrass meadows.  

Benefits

In addition to being a carbon sink, seagrasses provide a number of additional co-benefits. When not overwhelmed by eutrophication or coastal pollution, seagrass can utilize coastal runoff nutrient and mitigate eutrophication. Recent estimates suggest seagrass meadows support the productivity of 20% of the world’s biggest fisheries through nursery habitat provision[25]. Wherever they are present in proximity to human populations they form a targeted fishing ground of significant importance to human livelihoods and well-being[26]. Seagrasses also provide key habitats for keystone species such as sea turtles.

Mechanism: Conservation, Restoration and Creation

Although there remains uncertainty on the total extent of global seagrass ecosystems, modeling has been developed that estimates the following potential for interventions:

• 35 Mha of existing seagrass can be protected through seagrass conservation

• 14.2 Mha of seagrass ecosystem, lost to degradation in the last 100 years, can be restored through seagrass restoration

• 143 Mha of potential habitat that could be suitable for seagrass can be planted through seagrass creation

The priority focus is seagrass conservation and restoration.

Techniques

Seagrass conservation practices are similar to the practices utilized in mangrove settings. Examples of notable successful conservation sites include small community led marine protected areas (MPA) (e.g., in Tolitoli and Baru Baru) and MPAs focused on protecting keystone species such as dugong (e.g., in Bintan). Conservation incentive schemes (e.g. community-led efforts to reforest degraded riparian vegetation such as in Wakatobi NP) are also indicated in certain regions.

Seagrass restoration presents certain challenges and opportunities regarding cost and survival rates. According to the most widely cited resources for costs of blue carbon ecosystem restoration, seagrass ecosystem total restoration costs average $383,672/ha (2010 USD). This is likely a high estimate, especially given a median survival rate of 38%. Recent exercises using volunteer manual planting are far cheaper at $16,000–$34,000/ha, depending on plant unit spacing. The same planting using paid labor ranges from $84,000 to $168,000/ha[27].

Specific techniques and practices have been tested to reduce costs and increase survival rates, but their application is not yet a widespread practice. Best practices for seagrass restoration include[28]:

• Plant enough plants or seeds (between 1000 and 10,000 shoots/seeds at a minimum) for effective survival and population growth rate.

• Carefully select sites and species,for instance, a sheltered location with adequate light. Priority areas include shallow neritic zone areas that are less affected by pollution and/or areas where a complementary pollution mitigation strategy is being applied, such as a pollution biofiltration technique.

• Remove existing threats prior to replanting, e.g. controlling pollution, dredging.

• Prioritize water quality in restoration plans. Poor water quality is a leading cause of restoration failure.

One particular study of importance used biodegradable hessian bags (burlap sacks) partially filled with sand as a means of distributing seagrass plugs. Economically, hessian bags appear to be a sound option for large-scale rehabilitation. Materials are inexpensive and sites can be established by simply throwing bags off a boat as opposed to transplanting which is slow and costly to establish, requiring expensive divers and specialist expertise to cover a much smaller area per unit time. Cost-benefit analyses for large-scale rehabilitation indicate that a sowing density of 1000 hessian bags/ha would cost $16,737 (includes cost of materials, construction, and deployment), whilst covering the same area using transplants would cost at least $27,593[29].

Another paper identified clear increased survival rates (doubled) associated with a critical mass (minimum of between 1000 and 10,000 shoots/seeds) of planting[30]. The larger initial number of number of transplants were more resistant in the long term.  

Fishing community-led efforts, using some form of hessian bag methodology, clustered for resilience, and observing the aforementioned best practices are best positioned to restore seagrass ecosystems for optimal cover, lowest cost and greatest co-benefits.

OCEAN FARMING

Recent analysis shows that as much as 30% of net primary production from growth of macroalgae is exported to deeper marine sediments where the carbon in these seaweeds becomes sequestered over long timeframes[31].   

Many coastal regions have the potential for extensive macroalgae reforestation and ocean farming. Those areas with economically depressed coastal fishing communities would be the highest priority locations. See map below for certain highly suitable areas.

Ocean Farming and Carbon: The Stats

The World Bank estimates the following impact from expanded seaweed farming over the next thirty years. While global seaweed production in 2012 was three million tons dry weight and growing at a rate of nine percent per year, increasing seaweed farming to 14% growth per year would generate 500 million tons dry weight by 2050[33]. Market development for potential uses for seaweed is critical to increase adoption of ocean farming[34].

INTEGRATED SEAWATER AGRICULTURE SYSTEMS (ISAS)

ISAS is a method of selecting halophytes (salt-tolerant flowering plants) and intentionally cultivating them in desertified, degraded or desert soils by introducing saline irrigation, for instance “ocean rivers”, to inland soils. This method of creating blue carbon habitats might be considered controversial due to the appearance of large-scale ecosystem manipulation. 

ISAS methods have been piloted in Eritrea, Mexico and Egypt. Globally, the range of ecosystems suitable for ISAS include coastal deserts, inland salt deserts and regions where salinization has occurred due to industrialized agricultural practices otherwise known as “secondary salinization.” According to a 2006 report,  secondary salinization has spread to one billion hectares globally and is increasing at a rate of two million hectares annually. An estimated 130 million hectares may be immediately available for halophyte cultivation[37].

ISAS and Carbon: The Stats 

According to the same report, halophyte production in a potential 130 Mha area has the capacity to assimilate 0.6–1.2 Pg of carbon per year, sequestering 30–50%  of this carbon in long-term soil carbon. Coupling with nitrogen-fixing salt-tolerant plants such as Prosopis or Acacia spp. could increase sequestration in soil carbon even further by two T/ha and grasses such as Panicum vergatum (or switchgrass) grown on degraded soil has been shown to increase soil carbon by 12% over 10 years[38].

Carl Hodges and Arthur Gensler of Seawater Works have explored partnerships with the Cucapah Indians of Mexico to apply this technology by bringing seawater through the Salton Sea of California, travelling through Mexicali and the Imperial Valley along the way. Other priority locations include India, Morocco, Pakistan, and the countries of the Middle East and North Africa.

ISAS systems can be utilized for production of shrimp, tilapia, salicornia (pickleweed) and mangroves. These species produce a host of products including proteins, oils, fuel, habitat and improve soil carbon. Salicornia, being a dense carbohydrate, can also be turned into sturdy building materials. The dense groundcover cools local climates and builds soil carbon. Other uses include medicines (for such ailments as digestive troubles and heart disease), fuel wood and timber, forage/fiber, chemicals (such as soda for soap-making and glass) and landscaping[39]. 

While this technique is still in a research and development phase, the potential boon to food security in very specific regions (i.e. coastal areas that are desertified and/or food insecure like California), makes this an attractive and potentially cost-effective strategy to explore. The blue carbon literature and funding sources largely overlook this mechanism.

BIOMIXING WHALE PUMP

Whales are charismatic animals and linking them with carbon sequestration in popular discourse could stimulate increased emotional connection to blue carbon. Restoring whale populations implies protecting whales and whale habitat which would have co-benefits of increased fisheries and other cascading impacts on the carbon cycle.

Whales continue to be threatened by killings, captures, bombings, plastic ingestion, and pollution. Creating more MPAs, reducing plastic debris and reducing chemical, oil and sonic pollution all are effective means for increasing whale population and health.

ABOUT “GEO-ENGINEERING” AND OTHER STRATEGIES

Based on actionable criteria referenced above by Lovelock, et al., this report focuses on potent and sometimes novel approaches within mostly conventional blue carbon mechanisms. Additionally, the report considers and assesses mechanisms for climate change mitigation known as geo-engineering.  

The spider chart below from Gattuso, et al.[41] explains the readiness and durability of other, ocean-based strategies being examined and developed.

Of particular note are strategies to increase net primary productivity of phytoplankton. Due to the charisma of marine megafauna like whales and significant co-benefits associated with their preservation, this report has featured the biological mechanism of whale pump and biomixing, with noted potential limitations of carbon effect.  

Ocean fertilization, the use of iron or other mineral nutrients to stimulate net primary productivity, has received much attention. Adding material to the ocean is potentially considered pollution and ocean fertilization is prohibited (except for research purposes by the London Convention and the London Protocol). The main arguments against fertilization include ecological risks (uncertain and unintended effects on biological life and food webs other than phytoplankton) and the scale and duration of fertilization activity. An assessment framework has been developed for future research. 

Alkalinization also receives considerable attention. This mechanism involves adding carbonate material (examples include limestone and olivine) to the ocean to reduce acidity, which would enable the ocean to absorb additional carbon from the atmosphere. Critics have expressed concern about the emissions footprint of mining and transporting alkalizing land material to the ocean weighed against its carbon capture potential. This mechanism is particularly interesting because of the co-benefits of reducing acidification of the ocean. As of yet, there is no reasonable scale testing and measurement of the net benefits from this mechanism. Of particular note is Project Vesta - focused on olivine weathering.

SUMMARY OF BIG IDEAS | STRATEGIES | PROJECTS | FUNDING GAPS | ADDITIONAL RESEARCH | INTERVIEWS

SUMMARY OF BIG IDEAS | STRATEGIES | PROJECTS | FUNDING GAPS | ADDITIONAL RESEARCH | INTERVIEWS

FUNDING MECHANISMS

Blue carbon projects (conservation, restoration or other) appear to receive a minority of global philanthropic funding associated with ocean and ocean environments.  FundingtheOcean.org (Foundation Maps by Candid) lists $8.3billion total dollar value from 51,412 grants given globally for oceans and ocean environments from 2009-2019. Using query terms common to blue carbon ecosystems, the number of global grants for blue carbon related initiatives from 2009–2019 totaled 175 less than 1% of total giving for oceans. For comparison, over the same period, “coral” received 2,004 grants for $206,100,000.

Financing blue carbon project implementation at scale remains the most difficult task for achieving conservation and restoration objectives (Vanderklift et al., 2019) and the investment mechanisms and desire to finance projects remain inadequate (Bos, Pressey, & Stoeckl, 2015).

There are a diversity of multilateral and national funds that are possibly funding mechanisms to influence Blue Carbon strategies. Philanthropy and debt purchasing or conversion are non-market, non-multilateral or national fund mechanisms that play a critical role in developing pilot projects that prove the funding hypothesis for the larger pools of capital and potential market based mechanisms. Carbon markets (voluntary and regulated) are still at an emergent stage, but are showing promise (e.g., see Seagrass Grow as of Sept. 2019—335,222 sq. ft. of seagrass planted).

Currently, interviews and the literature recommend leveraging private funding to developing a network of demonstration projects which is needed to show the viability of blue carbon and to work out in a practical way the problems and pitfalls of running a project. Blue carbon as a vehicle for conservation, sustainable use and restoration also needs to be fully integrated into existing national and regional policy frameworks as a mechanism for climate change mitigation. Most projects have suffered from poor management protocols, such as not having proper success or failure criteria and have suffered from poor or uncertain methodology.

During the interview process informing this report, interviewees were asked to identify some of the “key players” to contribute to the space. Of the 13 interviewees, the themes of Coastal communities (referenced by 9 interviewees) and fishermen (referenced by 6) were the most commonly referenced key players. Upon entering the search key “fishermen or fisherman” in the Funding the Ocean database, global funding for initiatives focused on supporting fishermen $32.3 compared to the search key “policy,” which received $146.5M globally. Coastal communities do appear to receive more funding than fisherman advocacy groups at $125.7M and coastal restoration received even more at $207.2M. However, the key players which were mentioned much less frequently in the interviews, by just a subset of 2-3 interviewees, indigenous communities which received just $27.8M of global giving and youth which received $17.6M globally. CBEMR appeared grossly under-funded, not even reaching the $1M mark, but receiving a paltry $38,058 of global oceans giving, according to Funding the Ocean. Additionally, ocean conservation and funding typically focuses on the charismatic habitats and species(such as coral), while ignoring many of our poorly known habitats, such as seagrass, and species that are of major significance to responding to the challenges of climate and food security. The conservation of lesser known habitats remains problematic in light of limited and finite conservation and restoration resources.

>> Key Players:
Priority funding areas that are currently under-funded

1. CBEMR

2. Indigenous-led initiatives

3. Youth-centered restoration and conservation

4. Focus on coastal fishing communities

5. Non-charismatic species such as seagrasses and species inhabiting salt marshes (such as salicornica)

>> Key Players: Organizations Conducting Important Research and Education Surrounding the World of Blue Carbon

Grid Arendal
Ocean Foundation
King Abdullah University of Science and Technology & Carlos Duarte
Blue Forests Project 
Blue Carbon Initiative / Ocean Forests Foundation
International Scientific Working Group on Blue Carbon
Chesapeake Bay Foundation
Worldview International Foundation’s Mangrove Restoration Project
Hawaiian Ahupua’a System of organizing land stewardship for the benefit of all
Japanese Satoumi Coastal landscapes that have been positively impacted by human interactions for millennia
Sri-Lankan Cascading Tank System Ancient method of paddy farming, or aquaculture
Indonesian Empang Parit Traditional ecological system of shrimp farming in tandem with mangroves

SUMMARY OF BIG IDEAS | STRATEGIES | PROJECTS | FUNDING GAPS | ADDITIONAL RESEARCH | INTERVIEWS

Coastal blue carbon in the context of climate change: More research on the adaptability of coastal blue carbon ecosystems in the face of sea level rise and extreme events is needed. 

1. Global importance of macroalgae as blue carbon sinks/donors. How much of macroalgae production becomes long term carbon storage as sediment on the seafloor? How to stimulate market demand for kelp and kelp derived products should also be researched.

2. What factors influence blue carbon burial rates and what management actions best maintain and promote blue carbon sequestration?

3. Oceanic Blue Carbon. In general, a greater understanding of the mechanisms for increasing oceanic blue carbon capture is needed, including developing our understanding of marine vertebrate carbon, marine viruses and fertilization and alkalinization.

4. Conduct research on how to reduce costs to implement coastal blue carbon restoration projects at larger scales.

5. Conduct interviews with funders to discover barriers.

6. Pilot projects that help mainstream the notion of geographic and community-informed suitability. 

SUMMARY OF BIG IDEAS | STRATEGIES | PROJECTS | FUNDING GAPS | ADDITIONAL RESEARCH | INTERVIEWS

SUMMARY OF BIG IDEAS | STRATEGIES | PROJECTS | FUNDING GAPS | ADDITIONAL RESEARCH | INTERVIEWS