Seaweed’s Moment: What ISS25 Taught Us About Seaweed’s Role in the Circular Economy

Last month, the 25th International Seaweed Symposium (ISS25) was held in Victoria, British Columbia. The event brought together researchers, Indigenous leaders, entrepreneurs, and policymakers from around the world to explore one of the most promising but often overlooked resources in the sustainability space: seaweed.

As the urgency of climate action grows, seaweed is moving from the fringes of environmental science into the mainstream of industrial innovation. With applications in agriculture, packaging, renewable energy, and marine restoration, seaweed is being recognized as a high-impact, low-input solution that can help advance the circular economy.

Why Seaweed, and Why Now?

Seaweed’s popularity has grown rapidly in recent years, and for good reason. As it grows, seaweed removes excess nitrogen, phosphorus, and carbon from the water, helping to improve ocean health and reduce the effects of pollution. It also provides food and shelter for marine species, supports biodiversity, and can help buffer against ocean acidification. Unlike most agricultural crops, seaweed does not require land, freshwater, or chemical inputs.

Its industrial potential is just as compelling. Seaweed is used in food products, animal feed, cosmetics, fertilizers, and more recently, as a base for bioplastics and renewable energy. These applications allow seaweed to replace carbon-intensive materials, reduce emissions, and support the transition to cleaner supply chains.

Many speakers at ISS25 noted that the rise of seaweed fits into a broader global trend. Companies and governments are beginning to shift away from linear models of production and consumption that rely on extraction and waste. In their place, a more circular and regenerative approach is taking shape. This kind of systems change is increasingly seen as essential for building resilient economies that stay within planetary boundaries.

A Long History, and New Horizons

Seaweed farming has long played a role in the livelihoods of coastal communities, especially in Asia. Countries like Japan, South Korea, and China invested early in large-scale cultivation as far back as the 1940s. Today, the global industry is evolving beyond food production into new applications that support climate goals and bio-based economies.

Among the most promising uses are seaweed-based bioplastics, bio-stimulants, fertilizers, and biofuels. Seaweed bioplastics offer a biodegradable alternative to fossil-based plastics, which contribute to microplastic pollution and take centuries to break down. Unlike corn or sugarcane-based bioplastics, seaweed does not require freshwater, arable land, or synthetic inputs, which makes it particularly sustainable.

Seaweed-derived fertilizers and bio-stimulants improve soil health and nutrient uptake without contributing to runoff pollution, which is a common problem with synthetic fertilizers. In energy, seaweed is being studied as a feedstock for biogas and bioethanol, offering high productivity without competing with food crops.

Although the carbon sequestration potential of seaweed farming remains contested, it is already having an impact by displacing high-emission materials and processes. The seaweed that naturally sinks to the ocean floor may sequester carbon, but commercial uses generally involve re-releasing that carbon. Even so, seaweed’s role in decarbonizing products and supply chains is becoming more important as global targets tighten.

ISS25: Challenges That Need to Be Solved

While seaweed holds real potential, ISS25 made it clear that the industry still faces major barriers. Below are two of the most significant challenges identified by participants and experts during the symposium.

1. Limited Infrastructure, Market Access, and Knowledge

Roughly 97 percent of seaweed production today comes from Asia. In other parts of the world, the industry is limited by a lack of local processing facilities, underdeveloped markets, and data gaps on cultivation methods suited to different species and climates. These constraints make it difficult for new regions to participate or scale up.

Who is working on solutions?

The Nature Conservancy presented its Regional Seaweed Services Model at ISS25. The tool was developed to address these regional gaps by offering tailored guidance on species selection, farming practices, and ecological impacts. It supports practitioners and policymakers in building region-specific seaweed strategies that are environmentally and economically viable.

2. Low Biodiversity in Cultivated Species

The seaweed industry often focuses on a small number of high-performing species. These are typically selected for their yield or market value and are often propagated through cloning. This practice reduces genetic diversity and leaves crops vulnerable to disease, climate stress, and other environmental shocks.

Who is responding?

Institutions such as Woods Hole Oceanographic Institution, USC Sea Grant, and Hortimare are developing strain-breeding programs that increase genetic diversity and improve resilience. Their work focuses on expanding the number of commercially viable species and improving their ability to adapt to changing conditions.

One of the most innovative tools showcased at ISS25 was Reef Adapt, which combines genetic, environmental, and oceanographic data to guide marine restoration and cultivation. The tool helps identify seaweed populations that are most likely to thrive in specific locations now and under future climate scenarios.

Biodiversity is not only important for ecosystem health. It also expands the range of biochemical compounds that seaweed can produce, making whole-plant biorefinery models more feasible. These models extract value from every part of the biomass and support the creation of multiple products from a single harvest.

The Role of Indigenous Knowledge and Stewardship

A central theme of ISS25 was the importance of Indigenous knowledge systems in shaping a more ethical and resilient seaweed industry. For generations, Indigenous communities along the Pacific Coast where ISS25 took place, have harvested seaweed in ways that prioritize regeneration, seasonal balance, and long-term stewardship.

As the industry grows, recognizing and supporting these traditions is essential. Indigenous-led approaches can serve as models for sustainable development and help ensure that seaweed farming benefits local ecosystems and communities. By integrating Indigenous principles with scientific innovation, the industry can avoid repeating the extractive patterns that have harmed marine environments in the past.

Conclusion: Seaweed Is a Strategic Asset, Not a Trend

Seaweed is no longer just a niche crop. It is emerging as a critical enabler of circular systems that are better suited to the climate and resource challenges of our time. With the right investment, science, and values behind it, seaweed can help clean oceans, decarbonize industries, create sustainable livelihoods, and build resilience in coastal economies.

For this to happen, the industry must overcome key challenges, including infrastructure limitations and lack of biodiversity. It must also ensure that growth is guided by long-term ecological thinking and inclusive governance. Seaweed has already proven its potential. The next step is turning that potential into a global, equitable, and climate-smart reality.

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Author: Jemma Eason

Views in this article are that of the authors and do not explicitly represent official positions Circular Business Association.

Jemma Eason is currently serving as a Data and Research Intern of Circular Business Association. She is a dedicated sustainability professional based in Victoria, BC, with a double degree in Economics and Environmental Studies and a minor in Global Development Studies from the University of Victoria. She specializes in qualitative and quantitative analysis, certification processes, and community engagement, aiming to drive effective, inclusive sustainability practices. 

Circular Business Association (CBASS) is an ecosystem builder that aims to rapidly replace out all unsustainable, linear products in the next 4-5 years with sustainable circular products to solve the climate and create a liveable world. We believe that no organisation can achieve sustainability on their own and thus we answer the ‘Who’ that needs to be assembled to get climate and sustainability commitments done.

All images obtained as free resource from Wix.