Seaweed Farming—The Cure for Climate Change?

“Macro-algae forests have the potential to replace fossil fuel energy, while removing 53 billion tons of CO2 per year from the atmosphere.”

Photo by Andrew Buchanan on Unsplash


Do you know the seaweed in your sushi rolls can help mitigate climate change and its negative impacts?


The carbon dioxide (CO2) in the atmosphere has reached the highest level ever recorded. The high levels of CO2 are leading to the growing global temperature and increasingly vulnerable marine ecosystems.


However, an analysis indicates by using 9% of the world’s ocean surface to farm macroalgae (seaweed), we can substitute biomethane from seaweed for fossil fuel whilst reducing the amount of CO2 to pre-industrial levels.


In addition to serving as biofuel and carbon sinks, seaweed can also address issues associated with marine and food systems. The multifunctional feature makes it the perfect cure for climate change.


Let’s take a closer look at the magical power of seaweed.


When seaweed is in the ocean, …

Photo by Brian Yurasits on Unsplash


Ocean covers 71% of the earth’s surface, absorbing great amounts of CO2 and heat from the atmosphere. It’s doing a great job of reducing global temperature but at the expense of becoming warmer and sourer.


Seaweeds—the fast-growing, long-life span oceanic plants—are good at capturing and storing carbon. According to a study, seaweed contributes 50% of carbon trapped in sea floor. A great fraction of that carbon can stay in the ocean for probably centuries.


Through photosynthesis, seaweeds absorb carbon, nitrogen and other excessive nutrients to generate new biomass (the material used for energy production) and produce oxygen. Therefore, seaweeds not only serve as carbon sinks but also heal the marine ecosystem by ameliorating acidification and providing habitats for marine animals.

When seaweed is in our daily life, …

Photo by Valentin B. Kremer on Unsplash


Do you know why Japanese have a long-life expectancy? One explanation is that they integrate seaweed into their daily diet. Besides sushi rolls, they have created various seaweed recipes.


The explanation is reasonable in some way. Edible seaweeds contain all kinds of nutrients, like antioxidants, proteins, minerals, vitamins, and fatty acids. Studies show having red, brown, and green seaweeds can help us reduce blood pressure, and prevent cancers, obesity and diabetes.


Moreover, no land, freshwater, or fertilizer are needed for seaweed farming. That is to say using seaweed for food can save resources as well as CO2.


Seaweed is good fertiliser or animal feed for farmers. As the fertiliser, it supports plants’ uptake of nutrients and assist them in prevention of soil-related diseases.


As the animal feed, it can help reduce methane gas (the major component of greenhouse gas emissions from agriculture sector) produced by cows. According to a research, putting a small amount of dried seaweed into a cow’s diet can help reduce up to 99% of methane gas produced by the cow.


For energy sector, there has been growing interest in using seaweed as biofuel. Research claims that many species of seaweed are high in carbohydrate content and low in lignin content, which make it perfect for producing bioethanol. Compared with soybeans and corn (which are widely used for ethanol production), seaweed is not only more productive but also land-saving.


The reality of seaweed farming

Even though non-profit, businesses and development organisations have recognised the diverse benefits of seaweed, the development of seaweed aquaculture is quite limited.


Up to now, most of seaweed products come from coasts of Asian countries, like China, Indonesia, South Korea, and Japan. That explains we can hardly buy local seaweed in Australia.


To use seaweed to tackle climate change, policymakers need to develop more policies to motivate people to farm seaweed and expand it. As consumers, we can spread these messages and start turning seaweed into everyday food.


13 Responses to “Seaweed Farming—The Cure for Climate Change?”

  1. Yilin Zhao says:

    I think of the example of algae eutrophication, I don’t know if seaweed is similar. When a plant dies, bacteria and microorganisms in the water may consume a large amount of dissolved oxygen when decomposing the plant, resulting in eutrophication of the water. Maybe it is necessary to strictly monitor the seaweed growth cycle.

  2. Yue Li says:

    Why does cultivation consume oxygen? Do you mean harvest? We do need to consider how to do farm it a good way though.

  3. Yilin Zhao says:

    Hi Yue, after reading your blog, I want to eat seaweed. If it can help not only human health but also have an impact on the global climate, maybe it will become our mainstream food in the future.

    However, I am still worried about whether the cultivation of seaweed will affect the water body because the cultivation of seaweed needs to consume a lot of water oxygen, which may affect the survival of animals in the water. Also, seaweed is shaded on the sea surface and may affect plants in other water bodies. Therefore, I am worried that the large-scale cultivation of seaweed may cause eutrophication of water bodies.

  4. yufeizhang says:

    After reading your blog, I get many interesting and useful info. I like eat seaweed, because it is delicious and healthy. But I had never known that seaweed plays such an important in controlling temperature. Thank you for sharing this blog with us! Your ideas are clear, and the structure of your blog is good!!!

  5. Yue Li says:

    I don’t know what you mean limit the CO2 uptake. First, farming seaweed will produce no emissions. Second, seaweed can capture CO2 and turn it into new biomass. So it will reduce CO2 in the sea.

  6. Yue Li says:

    I didn’t see any drawbacks actually. But some commercial seaweed farming is being developed in Europe and east America.

  7. Yue Li says:

    As far as I know, it’s easy to harvest. But in Australia most seaweed is cultivated for fertiliser. Maybe because there’s much less demand for seaweed as food or other products in Australia compared with Asian countries, I just guess.

  8. Xiaoxue says:

    This is the first time that I know seaweed has so many profits. Very comprehensive!🥰

  9. Caroline Norton-Smith says:

    Hi Lui. I can see so many opportunities for Australia with our huge coastline – and large number of methane producing cows. I
    am interested as to why it is only not-for-profit companies that are producing seaweed in Australia – is it difficult to harvest?

  10. Haiwei Wang says:

    Wow, this sounds quite revolutionary, and the idea is so creative – I never thought to take to the oceans for farming. Is this being/going to be implemented commercially or are there some drawbacks?

  11. Thomas Hueneburg says:

    Great blog but I do not really understand how farming seaweed can reduce the CO2 level. Should it not be the opposite? By farming seaweed from the oceans we limit the amount of CO2 uptake and thus, permitting global warming.

  12. Roman Ulyanov says:

    Sounds like a great idea on all fronts. It’s a shame it’s not a widespread practice – I wonder why that is? Very interesting post!

  13. loik says:

    Although there’s all this potential for seaweed products which is likely more prominent in the future market, wouldn’t this mean a greater risk for those who are very allergic to iodine, a major component of seaweed, especially if more products contain seaweed?