Kelp: Food, fertilizer … carbon storage fantasy?
Seaweed farming holds many promises. Find out how kelp would fare as a climate solution. And take action!
Dear Climate Culinarians,
I got entangled in kelp. And I don’t mean the “sea monster catches swimmer” kind of entanglement. That was a tale kids would tell each other when I grew up: We’d swear there are underwater plants - plants! - that would grab your foot und pull you under. And here I am, writing to you about kelp, which looks like an underwater plant. The horror?
The long, brown-green blades belong to an algae, not a plant. So I guess we’re safe. That said, kelp actually pulls a lot, but in a good way. It doesn’t devour juvenile swimmers, but it pulls carbon dioxide out of the water. Kelp also raises the ph level - counteracting ocean acidification. Sounds like the perfect climate solution!
But there is a catch. Actually, more than one.
In this newsletter, I’ll write about
How kelp may serve as a climate solution,
why kelp isn’t a silver bullet,
how marine scientist Christopher Gobler and kelp farmer Sue Wicks try to solve problems with kelp,
(read about their personal journeys into researching/growing kelp in Part 1)
and what you can do to help – and have fun with - this fascinating seaweed.
New here? Every month, Climate Culinarians picks one topic and publishes a series of newsletters about it, ending with a recipe (see the weekly structure here). June is all about a seaweed called kelp. You already missed one post about it - sign up to get it delivered fro free!
How kelp stores carbon

Kelp guzzles down CO2 like a group of teenage boys let loose in a pizza parlor. That’s because kelp is one of the fastest growing beings on the planet. And growing requires lots of energy, in teenagers as well as in seaweed. To get that energy, kelp photosythesizes: It makes oxygen and sugar by absorbing sunlight and carbon. When kelp dies, it sinks to the ocean floor, taking most the locked carbon with it.
Kelp literally becomes a carbon sink.
However, this won’t work when you farm kelp on ropes and then cut it off for harvest. “If it all dies and then the CO2 is respired back, well, then it’s no net gain”, says Christopher Gobler, a coastal oceanographer at Stony Brook University’s School of Marine and Atmospheric Sciences. Like plants on land, disintegrating kelp releases carbon. Unless … you put it into the soil.
Just a few weeks ago, kelp farmer Sue Wicks delivered a truck load of fresh kelp to Stony Brook University’s food program - and dumped it onto one of their vegetable beds. “We have been using kelp as a soil supplement, and in that case, we have seen that some of the carbon gets retained in the soils”, says Gobler.
And how do vegetables react to their new neighbor from the ocean? They have dinner with it. And they seem to love the nutrients kelp brings to the soil. It is too early to tell if kelp can help replace fossil fuel-based fertilizer, preventing new carbon emissions. But Gobler’s experiments with vegetables and flowers look promising. “We can get growth rates with the kelp that are just like a commercial fertilizer”, the marine scientist says.
However, carbon does not stay in the ground forever. Soil gains carbon, or loses it, depending on the way the soil is managed, the soil type, and climate conditions.
What blocks kelp from becoming a super climate solution
Still, the concept of “carbon capture” remains stubbornly popular. One idea made hurricane-sized waves: dumping carbon-filled kelp into the deep sea. Scientists doubt that adding massive amounts of nutrients to the sea floor is a good idea. Nevertheless, investors were thrilled. Then it turned out the process is way more difficult than the idea lets on. Expensive, too. A company called Running Tides went out of business in 2024, after failing spectacularly with its deep-sea-kelp-carbon-sink approach (read more about their story at Canary Media).
“We are not going to solve the global CO2 problem with kelp”,
says Gobler.
“But on an oyster farm, for example, you could potentially make those oysters more resilient against acidification by co-growing them with seaweeds like kelp.”
Temporary carbon capture, increased biodiversity, alleviated ocean acidification: There are many reasons to support kelp farming and the restoration of wild kelp forests.
Here’s the catch: Kelp is a coldwater seaweed. And temperatures are on the rise due to climate change. In the ocean, too.
Gobler will not have to worry about old age for many years. But he is old enough to remember different weather patterns. To marvel at today’s bacteria counts in the water, at erratic storms, at ocean heat waves. At work in his Long Island lab, he observes the consequences. “In our waters, the kelp growing season is shorter than it used to be.” The window will continue to shrink, Gobler thinks.
Could New York aquafarmers add a warm season seaweed instead? The search is on. But if seaweeds aren’t native to an area, they might cause detrimental changes to coastal life. Marine scientists certainly have a boatload of research work cut out for them. And I’m sorry to say this, but … there is another problem.
Why environmentally beneficial kelp has a scaling problem
Chris Gobler makes sure I understand that this next area lies beyond his expertise: business. He often works with shellfish und kelp farmers, and from what he observes, the one thing that gets in the way of growing seaweed farming to a larger scale is finding a market.
The catch: Kelp farming costs money and requires labor - and then, what?

Oyster and kelp farmer Sue Wicks found buyers for her kelp. Most of it goes to fertilizer production, some of it to restaurants or food companies. Wicks fondly remembers how she started out and experimented with the help of local nonprofit East End Food Institute: Her kelp became an ingredient for hot sauce, soup stock, and a seasoning “that can go on eggs, avocados, fish, it’s very tasty”. And in terms of kelp as food, Wicks sees opportunities beyond taste.
“We have to stop relying solely on land”, Sue Wicks says, “and use less land, less fertilizer, and less fresh water to get our nutrients.”
Today’s agriculture is intense, using lots of resources on just a small variety of plants or livestock. Meanwhile, climate change increasingly brings harmful weather and pests that can wipe out whole harvests. One idea to reduce these risks? “We have to expand our palate”, says Wicks. And of course, she has a particular expansion in mind.
Who wants to eat seaweed?
A typical reaction I get when I serve a meal that contains kelp: A fork with a bit of seaweed is shoved in my direction, closely followed by “What is this?”. When I tell Sue Wicks, we realize that we have something in common: We love to share food, but we don’t push it. “I cook with my kelp and I’ll put it on my Instagram, showing how delicious it is and how it can be utilized”, says Wicks. “But I don’t get a lot of takers, you know, people wanting to buy kelp.”
Wicks thinks it’s a PR problem, and that means it can be solved. She can totally see kelp as the new kale. Due to a very short season for fresh kelp, she also compares it to asparagus - and dreams of a Long Island Kelp Week, celebrating the local harvest.
Now, I do love kelp, too. But I think as a kelp farmer and enthusiast, Wicks might be biased. Unfazed, she reminds me how sushi was a novelty in her youth. Now you grab it at Seven Eleven. Kids munch seaweed chips from Korea. “You see it in the food industry when you have an abundance and it’s economical”, Wicks says about the introduction of previously unkown food. And that might be the solution and the problem in one package.
Why processing is a problem for kelp (and what to do about that)
Kelp is not being farmed at scale in the U.S., and that comes with economic disadvantages. Wicks farms about two acres in the ocean. If she tried to brag about this size to a land-based farmer, they’d probably buy her a beer - out of pity. In China, yearly kelp production is measured in tons. In the U.S., it’s measured in pounds.
The catch: It’s hard to find a kelp processing plant.
Kelp does not keep too long after harvest. Therefore, there is hardly an American market for fresh kelp. It is either blanched and frozen, or it is dried. Both methods require considerable resources.
Processing kelp has been a struggle even in Maine, the largest farmed kelp region in the U.S. Eventually, investors helped build a processing plant with its own harvest pickup. But that is too far away from Long Island, where Sue Wicks was the first New Yorker to get a licence for commercial kelp farming.
I ask Wicks if she had to buy gigantic freezers for her harvest. She laughs and says no. “I want to be as close to net zero energy as possible.”
So she had to get creative. Together with a foundation dedicated to kelp farming, Lazy Point Farms, she build her own kelp drying plant: two shipping containers with a sheltered space in between. “We start drying our kelp in the outdoors, and then we put it in the shipping container that we retrofitted to make it a dehydrator”, Wicks says. Inside, dehumidifiers, heaters, and exhaust fans are humming, drawing energy from solar panels.
It wouldn’t be too hard for other kelp farmers to copy her processing construction. And that, too, is by design.
Take action: Seaweed and climate change
Get seaweed onto your plate. The easiest way to expand your diet is through dried seaweed. You’ll find kelp (or kombu) and other varieties in natural food stores, often imported from Asia. American seaweed companies like Maine Coast Sea Vegetables offer recipes online, along with kelp and other seaweeds.
Get seaweed in the ground. Ask your garden center if the have any fertilizers based on kelp or other seaweeds. Try it out and start your own veggie growing experiments.
Get hooked. Look into coastal ecosystems and fish around for a creature that fascinates you. Is it a tiny crab, a wavy seaweed, a clam hiding in the sediment? Learn why it’s important to its environment, and to humans. Share what you found out with a friend.
Get into the (sea)weeds. Learn more about kelp farming. Organizations like Green Wave and Lazy Point Farms directly provide kelp farmers with resources and advocate for the trade. Some environmental organizations, for example, the World Wildlife Fund, have programs to support seaweed farming. Most of them look for public support.
Get into the sewer. Runoff from septic tanks or outdated sewage systems is a major problem for coastal ecosystems (and lakes, too). Do some research where your poop is really going (your kids will love this!). Or ask your local news outlet to write an explainer about it - including environmental risks and solutions.
Get together to advocate for renewable energy. Join an organization that advances the transitions from fossil fuels to renewables in your area. You may find a group that organizes phone banks or meetings with representatives, a bunch of activists building community solar energy, a creative task force helping with messaging, there are many options. Find inspiration at 350 (including trainings) and Rewiring America.
Okay, time to untangle and enjoy a breeze of salty air. Who wants to put their feet up and engross themselves in a book? Next week, I’ll send you my recommendations, one of which will involve unexpected seaweed munchers called … nope, you gotta wait and read.
Eat, read, repeat!
Petrina
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Climate Culinarians is a project by me, Petrina Engelke. I write about climate and food, and I help other writers turn their ideas into a book people want to read. In other words: I’m a journalist and a book coach. Read more about this newsletter & me here.