Seaweed—A Potential Missing Piece in the Climate Puzzle

Seaweed has tremendous potential to deliver on industry’s goals of clean supply chains and climate-positive products and services.

Ongoing climate research in human health, coastal community resilience, and agriculture environmental impacts may all find their solutions from the same naturally occurring source: seaweeds. With ever increasing natural disasters due to climate change, it is believed by researchers at Running Tide and the Bigelow Laboratory of Ocean Sciences that harnessing the power of seaweed could unlock answers for reducing atmospheric carbon and global food insecurity.  

Seaweeds have long provided a sustainable source of food for people, particularly in countries where seaweed is found in many traditional meals due to ready availability. Seaweed farming (also known as aquaculture) for human consumption has been practiced for thousands of years to support local food supplies all over the world. Seaweed aquaculture provides much needed protein and vitamin sources for human health, in addition to contributing habitable environments for marine species and acting as a carbon sink, a key counter measure to climate change. However, overfishing and marine habitat loss may create food insecurity amongst the nearly three billion people globally that rely on seafood as their primary protein source. A possible panacea comes in the form of large-scale seaweed aquaculture to supplement land and seafood systems.  

Seaweed cultivation doesn’t require land, freshwater, or fertilizer – all benefits when compared to the environmentally devastating livestock industry. Yet, scientists warn against jumping into mass-harvesting due to difficulty in global scaling. Seaweeds have temperature and nutrient requirements for growth, and increasing ocean acidity due to climate change can impact the growth success of aquaculture species. Additionally, a review in 2019 highlighted the risks of introducing farms into vulnerable habitats, possibly upsetting current ecosystem balances.  

Despite these concerns, increasing global food production using aquaculture can still be a great step in reducing pressure on land-based food systems. Currently, agriculture is only increasing as the global population, and therefore demand, increases. A study in 2019 concluded that livestock were responsible for 14.5% of global greenhouse gas emissions in the form of methane. Again, seaweed is praised as a solution  – adding the red algae species Asparagopsis taxiformis to cattle feed in a controlled study demonstrated a reduction in methane production by up to 99%. However, during a commercial trial, the feed supplementation only had a 28% methane reduction outcome. Differences in livestock breeds, environmental factors, and long-term health impacts need to be studied to fully determine the efficacy of feed changes.  

In remote coastal communities, the effects of seaweed farming are largely positive. New farms create new jobs. Industry job creation not only bolsters the economy but also helps to create community resilience to climate change. In First Nations communities on the Pacific Coast of Canada, job seekers are often forced to leave their homes to find work elsewhere. An influx of aquaculture in coastal towns can provide much needed jobs. In Tanzania, seaweed farming is a crucial source of livelihoods for coastal communities. Nonetheless, incoming corporations and strict regulations pose threats to vulnerable groups as the seaweed aquaculture industry continues to grow.  

Questions remain about whether seaweed solutions can be scaled globally to combat climate change. A 2023 study suggests that social and ecological risks of large-scale seaweed production are poorly understood. Producing seaweed at the scale necessary for significant climate change reduction is unlikely in the near future and many knowledge gaps remain. Still, the environmental benefits of seaweeds are clear. They are essential for marine biodiversity and human health, create beneficial habitats for marine species, and sequester carbon. The aquaculture industry continues to grow, with global seaweed production doubling in the last decade, lending hope to a climate-anxious world.