Is Farming Seaweed a Solution to the Climate Crisis?


Kelp Forest"Kelp Forest" by NOAA's National Ocean Service is licensed under CC BY 2.0

It started with a podcast...

Until recently, I didn’t know much about seaweed at all. I knew that kelp, a type of seaweed, was important to Southern California’s coastal ecosystem, but I wasn’t exactly sure why. At some point I probably learned about it at a Surfrider Foundation chapter meeting but that had to have been years ago. So without giving it much thought, I’ve just watched its flowy fronds float by my board, morning after morning, in the surf lineup. But a recent podcast episode introducing me to seaweed farmer, Bren Smith, would change how I looked at kelp and would bring seaweed to the forefront of my mind when climate solutions are discussed. 

Bren Smith captivated me instantly. Born in a small fishing village in Newfoundland, dropping out of school at 14 to become a commercial fisherman, and finding his way to the Bering Sea to work on a fishing boat hunting cod and crab was a far cry from the environmentalist he would become. And that’s what fascinated me. He understood first-hand that we are pillaging our oceans and it's unsustainable. Bren would go on to the University of Vermont, start a regenerative ocean farm raising kelp and shellfish, and found the nonprofit GreenWave that helps others get started on their own ocean farms. His story inspired me. I began reading all about kelp farms and the role they could play in our fight against climate change. 

 surfing among kelp bedsBefore learning about seaweed as a solution to the climate crisis, I only occasionally thought about this aquatic plant when it would float by in the water

Why farm seaweed?

We’re all familiar with the role trees play in sequestering carbon. They draw in the atmosphere’s CO2 and through the process of photosynthesis, release oxygen as a by-product. Many environmental campaigns focus on planting trees, and for good reason; our forests play a crucial role in providing us with the air we breathe. Less attention, however, is paid to the rate at which this process is happening underwater. Over half of the oxygen we breathe is actually thanks to ocean photosynthesizers like seaweed. Kelp forests (a type of seaweed) have been deemed the rainforests of the ocean so when we think of protecting forests, it’s critical that we don’t forget about the aquatic ones!

In response to the climate crisis, though, seaweed is receiving attention that goes beyond the importance of protecting it. Research has shown that responsible farming of seaweed could play a major role in solving many of the challenges we’re facing on a warming planet. Now, farming doesn’t always conjure up images of the pinnacle of sustainability, especially when it comes to the ocean (I just think of salmon farms and shudder). But growing seaweed is different. Bren calls it “regenerative ocean farming.” His polyculture model uses floating ropes from which kelp grows and baskets of shellfish hang. This results in a small footprint compared to farming on land since the entire water column is put to use (3D farming) and kelp requires zero inputs (like fresh water or fertilizer). 

Key benefits of seaweed and seaweed farming

Like trees that draw in CO2 from the air, seaweed draws in CO2 from the ocean. This sequestering of ocean carbon is critically important for a healthy marine ecosystem. The ocean draws in about 30% of the atmosphere’s CO2. Therefore, as atmospheric CO2 levels rise, so does the amount of carbon in the ocean. This increase in ocean carbon is leading to a drop in the ocean’s PH levels (i.e. ocean acidification) which negatively impacts marine life, especially shell builders. An increase in seaweed production would draw carbon out of the ocean and create localized de-acidification zones that help restore marine ecosystems and create a favorable environment for shellfish growth.  

Since seaweed creates ideal conditions for shellfish, they’re often grown alongside one another on seaweed farms. This polyculture approach creates biodiversity in the water leading to even more benefits. For example, oysters can filter as much as 50 gallons of water in a day! To top it off, since regenerative seaweed and shellfish farms are out in open water, they provide refuge for marine wildlife leading to habitat restoration.  

It’s clear growing seaweed has some pretty amazing benefits when it comes to maintaining a healthy, balanced ocean environment. But say we really ramp up its production to reap these benefits; now what do we do with all this seaweed? The possibilities really seem endless and there are likely uses that are yet to be discovered! But here’s what experts are excited about right now. 

Currently, seaweed is predominantly used in food, medicine, and beauty products. Seaweed, if scaled up, has the potential to be converted into biofuel and can also be used to create bioplastics. Biofuel and bioplastics are by no means perfect solutions, but seaweed could compete with fossil fuels and would also be a more environmentally friendly alternative to land-intensive crops like corn or sugar. While many parts of the world already incorporate seaweed into their diets, seaweed promises to be a sustainable and nutritious food source for the growing human population. And if you thought that seaweed couldn’t get any more impressive, research has shown that adding it to cattle feed significantly reduces methane emissions! With all of seaweed’s environmental benefits and its myriad potential uses, seaweed farming also promises the creation of millions of jobs

Final note  

Seaweed farming, as I’m learning with all potential climate change solutions, is no silver bullet. To avoid negative, unintended consequences, we’ll have to ramp up its production mindfully, responsibly, and backed by research. We have to take on climate change from so many different angles, and this is just one. But Bren’s story and seaweed’s promises have me hopeful (and pretty excited) that we’re on our way to solving another piece of this daunting puzzle. If you want to learn more about regenerative ocean farming and Bren's model, I strongly recommend checking out GreenWave’s website for more information and for links to many relevant news articles and research reports. And finally, if seaweed isn’t already part of your diet, I encourage you to give it a try! It’s pretty tasty :)

Listen to the podcast that inspired this post! How to Save a Planet: Kelp Farming, for the Climate 

Fish Sounds - Kelp Forest"Fish Sounds - Kelp Forest" by California Sea Grant is licensed under CC BY 2.0

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