Seaweed: Prospects for Decarbonisation and Food Security in Southeast Asia

INTRODUCTION

Some have called seaweed “an important piece of the climate puzzle”, “an environmental powerhouse”, and the “fastest and least expensive way” for carbon mitigation. In a 2023 report, the World Bank added that the global seaweed market could grow by an additional US$11.8 billion by 2030, and that seaweed has the potential to improve marine biodiversity and alleviate poverty, especially among those most impacted by sea-level rise.

One-third of global farmed seaweed is produced in Southeast Asia. Can the region’s nations leverage seaweed not only for socio-economic development, but also for food security and decarbonisation?

SEAWEED USE IN THE FOOD SYSTEM AND ITS POTENTIAL

Up to 85 per cent of farmed seaweed is currently used for non-staple foods and food ingredients. It is a good dietary source of micronutrients, fibre, and antioxidants. Seaweeds are a typical part of Chinese, Japanese and Korean cuisines, all of which continue to grow in popularity globally. Indonesians and Filipinos use seaweed for desserts, and a small minority use it for salads, soup, flavourings and snacks. In Malaysia, it is added to rice for Nasi Kerabu.

As an ingredient, seaweed is used in both edible and non-edible items. Dried seaweed is sold as hydrocolloids (as carrageenan), which is used as a functional ingredient in food formulation to improve food consistency, as an emulsifier and to control texture, flavour, and shelf life. It is used in pharmaceuticals, cosmetics, and as a dairy and meat texturiser. Another popular species, Gracilaria, is used as agar to stabilise and thicken food.

Beyond food and non-food ingredients, some seaweeds are used as feed for abalone aquaculture and as a feed additive for shrimp and livestock due to their potential to boost immune systems and enhance growth. For humans, there are also growing nutraceutical applications. Seaweed is also being used as feedstock for alternative protein products, including plant-based meat.

Certain seaweeds can also contribute to food security as a biostimulant by increasing plants’ abilities to absorb nutrients; this aligns with organic farming. It contributes to plant resilience as well; for example, one seaweed species has been found to improve plant health under saline (salt water) conditions in the Netherlands, boosting root vegetable yields in the face of sea-level rise. The World Bank highlights that seaweed bio-stimulants are worth a US$1.9 billion opportunity as an alternative to fossil fuel-sourced fertilisers and pesticides. Seaweed also contributes to food security indirectly by providing ecosystem services for fisheries. It provides food and habitat for marine life and is an effective bioremediation tool that enhances water quality by absorbing nitrogen and other undesirable chemicals.

Seaweed farming is also an alternative income source for rural communities, uplifting communities – particularly women – from poverty. This allows families to consume a wider variety of foods, including protein products, contributing to better health outcomes.

SEAWEED’S POTENTIAL FOR DECARBONISATION

Seaweed cultivation has been identified in the Intergovernmental Panel on Climate Change (IPCC)’s Special Report on the Ocean and Cryosphere in a Changing Climate as a potential means for biosequestration of carbon dioxide and reducing ocean acidification. However, its potential for decarbonisation is not straightforward.

Through photosynthesis, seaweed absorbs carbon dioxide. A number of companies and research organisations have been experimenting with the cultivation of seaweed to sequester carbon and sink it in the deep ocean floor in exchange for carbon credits. The science of its efficacy and health impacts on marine and aquatic ecosystems is understudied, however, and researchers and policymakers are cautious of viewing it as a pathway of permanent carbon removal due to the inability to monitor, report and verify such credits. At least one such US-based company, with US$70 million in investment, has recently shuttered due to its inability to sustain its operations by sale of such carbon credits.

Carbon captured in seaweed biomass used for consumption (as food, feed or ingredients) or combustion (as fuel or bioplastics) is eventually released, and thus cannot be considered as contributing to decarbonisation. While some carbon is sequestered when fronds break off and sink to the seafloor as sediment, research has found that the amounts are small. A recent report by the Nature Conservancy and Bain Consulting suggested that, based on current carbon prices (averaging US$30 per ton CO₂e), carbon markets are unlikely to drive growth in seaweed farming, though this could change if carbon prices were to increase a few-fold.

Recent research has demonstrated that the use of Asparagopsis taxiformis and armata as feed additives can decrease enteric methane production in cattle by up to 80 per cent, though long-term studies are needed to confirm this. Cattle farming contributes approximately 7 percent of global greenhouse gas emissions, much of this due to enteric methane production. At least one company has started growing Asparagopsis in Vietnam.

Seaweed can also potentially mitigate carbon emissions by replacing plastics, petrochemicals and other fossil-fuel based products. Red seaweed biomass could, in a distant future, potentially even be used for biofuel production because its productivity (dry weight per unit area per year) is higher than that of wood and agricultural waste. Some seaweeds have high lipid and low lignin content suitable for efficient biofuel production, including Gracilaria, comparable to sorghum and sugarcane, however, past attempts to commercially produce biofuel from seaweed have not been successful. Other studies have shown that Kappaphycus and pure κ-carrageenan have the potential to be made into biofilms that are suitable for single-use packaging, though these too have yet to be widely adopted.

As seaweed does not require arable soil or chemical inputs, it is seen as an attractive third-generation feedstock to help power a future bioeconomy. However, the lack of availability of sufficient volumes of seaweed at low prices and consistent quality is a limitation. Even though it is already being added to bioplastics now, the current purchase price of raw materials is a significant barrier, as adoption prices for seaweed-based bioplastics are currently 20-40 per cent higher than conventional plastics. Scale and the domestic infrastructure for processing at scale would be critical to develop a seaweed biofuel and bioplastics industry.

SOUTHEAST ASIA’S SEAWEED INDUSTRY

Southeast Asia has a longstanding history of seaweed farming and produces more than 32 percent of globally farmed seaweed. Widely cultivated tropical seaweeds have a fast development cycle of approximately 45 days, do not compete with agricultural land, can be grown without fertiliser input, have limited carbon emissions, and can be grown all year round, and are thus ideal as a sustainable produce for Southeast Asia.

Widely cultivated tropical seaweeds have a fast development cycle of approximately 45 days, do not compete with agricultural land, can be grown without fertiliser input, have limited carbon emissions, and can be grown all year round, and are thus ideal as a sustainable produce for Southeast Asia.

Indonesia and the Philippines are the second and fourth-largest seaweed producers in the world, respectively. Malaysia, Vietnam, Cambodia, and Timor Leste also produce seaweed (see Table 1). Indonesia alone produces more than 75 per cent of global cultivated tropical seaweed. Southeast Asia’s seaweed production mainly consists of tropical species of Gracilaria and Eucheumatoids. These are used for direct consumption, feed for aquaculture, or processing into agar, and carrageenan. The main export market is China, which is also a major producer, but a net importer.

Seaweed is mainly farmed as an alternative income-generating activity for hundreds of thousands in the region. It is commonly farmed by women and is seen as an efficient use of family labour. Due to seaweed farming’s contribution to rural livelihoods and its economic potential, the governments of Indonesia, Philippines, Malaysia and Vietnam have recently been motivated to support seaweed production. Most Southeast Asian seaweed farmers practise a very basic form of cultivation, and any improvements could potentially improve yields significantly.

Table1: Production of seaweed in Southeast Asian nations

	Production in Tonnes (2020)	Percent of global production	Dominant types of seaweed
Indonesia	9,680,000	~ 28.6%	Eucheumatoids (Kappaphycus alvarezii, Eucheuma denticuatum), Gracilaria, Sargassum Caulerpa, others
Philippines	1,500,000	~4.19%	Eucheumatoids (Kappaphycus alvarezii), Gracilaria
Malaysia	182,100	~0.53%	Eucheumatoids (Kappaphycus alvarezii)
Vietnam	12,900	minimal	Eucheumatoids (Kappaphycus alvarezii, Kappaphycus striatus, Eucheuma denticulatum) Gracilaria, Caulerpa lentillifera, Sargassum
Cambodia	1,000	minimal	NA
Timor Leste	700	minimal	NA

Indonesia became the second-largest seaweed producer in the world, surpassing Philippines’ in 2007. It is the world’s major producer of Gracilaria, Kappaphycus alvarezii and Eucheuma denticulatum. The government has introduced a roadmap for seaweed industry development by introducing regulations and legislations to empower seaweed farmers and manage and license coastal zones. Indonesia’s Ministry of Marine Affairs and Fisheries (MMAF) has nominated seaweed as one of its top three priority commodities for aquaculture development in Indonesia for 2021-2024 (along with shrimp and lobster); only 2.3 per cent of Indonesia’s seascape is used for mariculture, but it has a potential for 12 million hectares. Indonesia is considering promoting seaweed production for biofuel.

After years of decline in production due to competition and extreme weather, the Philippines is also priming to expand its seaweed industry. Its Department of Agriculture’s Bureau of Fisheries and Aquatic Resources released its National Seaweed (Kappaphycus) Industry Roadmap 2022-2026. According to the Department, seaweed is the primary aquaculture commodity, and more than a million Filipinos depend on the industry. The Philippines Rural Development Project identified seaweed as one of the eight “commodities of national importance” that are priority crops for development and trade. The Philippines has 700,000 hectares of farmable area, but only 8 per cent of it is currently being utilised; the goal is to increase quality and seaweed production by 2 per cent annually. Its Seaweed Technology Development Centre is crucial in enhancing seaweed farming through R&D.

Vietnam is targeting to harvest half a million tonnes of seaweed annually by 2030. Malaysia, on the other hand, is lacking in serious government direction to expand the seaweed industry, even though it was the third-largest producer of carrageenan seaweed in the world in 2010, now dropping to the top 20.While R&D has been taking place in Malaysia, it has reportedly not translated to production or quality improvements for the industry.

While governments have set out plans to grow seaweed production, production volumes and yield have actually been falling in recent years. Indonesia’s seaweed production has been steadily declining since its peak in 2015, and this is mirrored in the Philippines to a lesser extent (Figure 1). The decline is primarily due to deteriorating seed stock quality, which is a result of the multi-decades-long practice of using vegetative propagation for farming. Seaweed production is also suffering from climate change-induced sea-surface temperature warming, immature processing technologies and volatile seaweed prices. 

Figure 1: Seaweed production volume in Indonesia peaked in 2015 and has been in decline since. 

RECOMMENDATIONS TO DEVELOP THE INDUSTRY

As the World Bank report highlights, the seaweed industry is ripe for growth. However it requires enabling policies and actions in Southeast Asia if its people are to reap the benefits.

Indonesia and Philippines have already developed roadmaps to expand and develop the industry, including expanding research and development (R&D) to improve cultivars and products, developing nurseries, facilitating access to new seaspaces to expand seaweed farms, empowering seaweed farming communities, developing value chain infrastructure, developing market linkages, providing training, facilitating technology transfer, and through industry promotion. Production also needs to be modernised and mechanised, especially as farmers are aging. Furthermore, production practices also need to move away from the use of plastic as floatation devices and strings, as these increase product contaminations and degrades marine habitats. These may moderate prices. Other Southeast Asian nations need to put in place similar policies and actions to expand their own seaweed industries.

As a region, however, much can be done to support the growth of the industry so that the benefits are exponential. This aligns with the ASEAN Blue Economy Framework (ABEF) released in 2023, which commits to regional cooperation in the blue economy, prioritising value creation, resilience, inclusivity and sustainability. Seaweed farming aligns with the ABEF’s Blue priority sectors, and when integrated with aquaculture farms, can promote fisheries development and resilience.

Based on the authors’ research, beyond strategies outlined in the ABEF, recommendations for action to further improve the seaweed industry include:

1. Regional collaboration on R&D and commercialisation of new products from tropical seaweed species. Despite existing national seaweed R&D programmes, industry stakeholders highlight that there has not been a breakthrough in commercial seaweed species in the last 50 years. Of the 12,000 seaweed species, only 12 species account for more than 95 percent of production, and only 5 are farmed in Southeast Asia. New products have emerged but have yet to be commercialised. The region is also heavily dependent on carrageenan markets; this is risky as there is always the potential for other food additives to replace it. For example, there has been pressure in the United States for the last decade to ban the use of carrageenan in organic foods, due to (disputed) reports by some scientists that it causes inflammation in the digestive tract. Such a ban may critically disrupt demand for Eucheumatoids. New off-takers are urgently needed to avoid the collapse of seaweed demand should similar disruptions occur. Regional collaboration on R&D is needed to avoid duplication of efforts and to expand the variety of seaweeds being researched and commercialised. This is particularly urgent as higher-yielding, resilient cultivars are needed to adapt to the ocean warming and acidification which are projected to occur. This aligns with ABEF’s Blue Strategy 2: Blue Science, Technology and Innovation.
2. Harmonisation of industry standards. While the standards for seaweed in food and pharmaceuticals are relatively well established, new industry standards are needed for its use for biostimulants, feed additives, bioplastics, biofuel and others. This will enable the industry to grow faster once downstream players use these standards to compare different seaweed-derived products against fossil-fuel-based incumbents. As this space is still nascent, it is beneficial to set standards early before practices become entrenched.
3. Creation of enabling environments on downstream industries and market linkages. Currently, seaweed is exported mainly in its primary form without industrial processing. This exposes farmers to highly volatile global prices. For example, a tonne of kappaphycus was sold for US$811 in 2007 but the price tripled to US$2,166 in 2008 and then dropped to US$1,208 in 2009. Creating an enabling environment for in-region industrial-scale processing facilities, for instance, by levelling the playing field between domestic and Chinese companies through tax treatment will benefit its economies and spur new downstream manufacturing activities.
4. Leveraging seaweed farmers for more accurate coastal monitoring. Southeast Asian nations lack the resources to monitor their coastal waters, even as their residents depend on marine resources for between 20 and 50 per cent of their protein. In the United States, at least one organisation, GreenWave, is leveraging its network of seaweed farms to capture data, which is licenced to interested parties. Similarly, governments could gather data from seaweed farms to understand the environmental conditions of their coastal waters and address pollution, long-term warming, or acidification trends. Establishing the monitoring ecosystem and the data collection capacity may take time; however, it does align with ABEF’s Blue Strategy 1 for Blue Conservation Management.

CONCLUSION

Seaweed is not a mere new flavour of the month, and has the potential for multi-fold benefits for the region. However it has a long way to go before it is sustainable. It has been farmed in Southeast Asia for generations, contributing to the resilience of coastal communities – particularly women – as a vital secondary source of income due to its low barriers to entry and short growth cycle. It is eaten as a food, used as a feed and processed as an ingredient for food, pharmaceutical and nutraceutical industries. It benefits fisheries and marine habitats. It also has potential for decarbonisation, particularly if used to displace fossil-fuel derived products such as fertilisers, fuel and plastics.

Altogether, the seaweed sector has the potential for multi-billion-dollar growth, and Southeast Asia could gain economically, but only if its governments take a longer-term view, collaborate, and create an enabling environment for seaweeds and their derived products to deliver their sustainability benefits over their fossil-fuel-based counterparts.

Altogether, the seaweed sector has the potential for multi-billion-dollar growth, and Southeast Asia could gain economically, but only if its governments take a longer-term view, collaborate, and create an enabling environment for seaweeds and their derived products to deliver their sustainability benefits over their fossil-fuel-based counterparts. It would require restructuring the industry to capture downstream processing and manufacturing activities. As this becomes more feasible, further investment will be attracted into the industry to improve production quality, which in turn would improve the applications of seaweed-derived products.

While some Southeast Asian nations have plans to grow the industry, the industry could be considerably boosted by regional cooperation in R&D and commercialisation, industry standards and market linkages. Data derived from seaweed farming could also be used for coastal monitoring. These align with the ASEAN Blue Economy Framework. To create this virtuous circle, governments need to support the aforementioned activities. Given the challenges that climate change poses to coastal communities in the region, enabling the seaweed industry to grow in ways that prioritise local development and resilience to climate change is an opportunity that regional governments cannot afford to miss.

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This is an adapted version of ISEAS Perspective 2024/88 published on 24 October 2024. The paper and its references can be accessed at this link.