Celebrate Life Below Water. Eat Blue

The second article in The Kelp Revolution: Our Seaweed Series

“Seaweed is finally having its moment in the spotlight” – Professor Halley Froehlich

The worldwide seaweed market is growing. At the same time, climate change is becoming a more severe and immediate issue. Like all industries, the seaweed farming industry should think about how it can play a role in solving the global problem of greenhouse gas emissions and planetary warming. Fortunately, there are some very exciting opportunities to create gigatons of greenhouse gas reduction by scaling up seaweed production. 

The first article in this series covered seaweed’s uses in products and industry. This second installment will zoom out and explore how seaweed can play a meaningful role in mitigating climate change. 

Kelp – Sequestration and Symbiosis 

If one were to dream up a plant designed to mitigate climate change, it would be hard to come up with something better than kelp. Like all plants, kelp uses photosynthesis to turn carbon dioxide into biomass. However, since kelp grows so fast (giant kelp can grow two feet per day in ideal conditions), it absorbs carbon dioxide very rapidly. One acre of certain kelp species can sequester 20 times as much carbon dioxide as one acre of forest.  

Kelp absorbs so much carbon dioxide from its surroundings that it can help counter ocean acidification, which is caused by excess carbon dioxide in the air forming carbonic acid in the ocean. Shellfish thrive in less acidic waters, and kelp farmers can capitalize on this symbiosis by farming shellfish as a secondary, co-located crop

The equation gets even better when one realizes how few inputs are needed to farm kelp. “No

freshwater, no fertilizer, no feed make [seaweed] the most sustainable food on the planet,” says Bren Smith, a commercial fisherman who has pivoted to focus on seaweed farming. He adds that “at the same time, our crops soak up carbon, nitrogen, rebuild reef systems. So, they really become engines of restoration as we’re farming and try to make a living.” To start farming kelp, farmers can float lines with kelp seeds in the ocean, and let the sun, seawater, and seaweed do a lot of the work.  

In 2013, Bren Smith founded a non-profit called GreenWave to educate other farmers about seaweed farming and regenerative ocean practices. According to a recent CNBC interview, GreenWave has trained 160 ocean farmers and they have a waitlist of another 6,000. As more farmers get involved, and seaweed farming continues to scale up, the resulting carbon sequestration will start to add up in the best way. 

Asparagopsis Taxiformis – Miraculous Methane Reduction 

Asparagopsis taxiformis (A. taxiformis for short) is a species of red seaweed which has positive climate impacts that extend far beyond carbon sequestration. A growing body of research has shown that when even a small amount of A. taxiformis is added to livestock feed, it reduces livestock methane emissions by over 90%.  

There are one billion cows worldwide each burping out 220 pounds of methane per year, and methane is a greenhouse gas that is 28 times more potent than carbon dioxide over a 100-year period. Once we start adding A. taxiformis to the diet of livestock, the greenhouse gas emissions reduction will be massive. 

Several startups including SymbrosiaCH4 Global, and Volta Greentech are working on scaling production of A. Taxiformis to supply farmers with this natural, climate-saving seaweed feed supplement. Symbrosia, a Hawaii-based startup developing on-land aquaculture systems to grow A. Taxiformis at scale, recently received a $250,000 grant from the National Science Foundation to continue their research and development. The world is watching as these companies work to scale production of this incredible species of seaweed to reduce livestock methane emissions at scale. 

Seaweed for Biofuel 

Today, the most common plant-based fuel is ethanol, a biofuel produced from crops like wheat and sugarcane. However, seaweed’s rapid, space and cost-efficient growth may lead to the forests of the ocean being a crucial raw material for the biofuel of tomorrow. 

In 2017, the US Department of Energy started the Mariner (Macroalgae Research Inspiring Novel Energy Resources) Program to fund groups developing scalable innovations in macroalgae production and the macroalgae biofuel space. “ARPA-E estimates the United States has suitable conditions and geography to produce at least 500 million dry metric tons of

macroalgae per year,” states the Marine Program website. “Such production volumes could yield about 2.7 quadrillion BTUs (quads) of energy in the form of liquid fuel, roughly 10% of the nation’s annual transportation energy demand.” The program currently supports 20 active projects in Hawaii, Alaska, and on both US coasts.  

You can be part of the Seaweed Revolution 

This decade is a crucial time for climate action, and it is important to be aware that seaweed is one of the many tools in our collective toolbox for mitigating climate change. Now that you know more about how seaweed can play a major role in solving climate change, feel free to share this information and keep an eye out for ongoing developments as all of these seaweed innovations scale. 

Interested in learning more? Read the Seaweed Manifesto, published in 2020 by the UN Global Compact and stay tuned as we explore the Kelp Revolution together in this Seaweed Series. 

Picture of Eli Etzioni

Eli Etzioni

Eli Etzioni is the Strategic Partnerships Associate at Fast Forward, the accelerator for tech-driven nonprofits. In the past, he has worked in bluetech as well as surf therapy, and he is equal parts climate optimist and outdoor enthusiast. He can often be found thinking about sustainable aquaculture while surfing or pondering climate-friendly transit options while biking ??.