The case for seaweed

By David Sheridan

​On 28th January 2021, Green Angel Syndicate members and guests will be watching a presentation from a company that uses innovative biorefinery methods to develop food products and bio-packaging from sustainably-farmed seaweed. 

​Environmental Benefits

Seaweeds provide the planet with enormous environmental benefits. By removing CO2 from the atmosphere, seaweeds reduce the concentration of CO2 at the same time as reducing harmful ocean acidification resulting from man-made carbon emissions. Seaweeds encourage marine biodiversity both in terms of habitat and nutrients.  Kelp, a seaweed that can grow as much as one metre long in a single day, is estimated to absorb five times more carbon than land-based plants. Seaweed farming is a new development designed to enhance the presence of seaweed while also providing a commercial return.  By increasing the carbon sink effect of seaweed, it will increase the ocean’s capacity for carbon removal from the atmosphere.. 

Image by Ben Davies from Pixabay

Economic Benefits

​Unlike conventional land-based agriculture, seaweed farming doesn’t require fresh water or fertiliser. And there’s no need to clear land to cultivate it. Added to this, when the economies of scale become effective, the capital cost of farming seaweed should be substantially lower than farming land based crops.  

Entrepreneurial Innovation

The sustainability of seaweed is one reason why entrepreneurs are investigating ways to scale up their production for a variety of goods, including food, fuel, pharmaceuticals and also packaging that can reduce greenhouse gas emissions and replace some of the plastic products that pollute both our land and our oceans.

CO2 Drawdown

​As well as sustainable products, farmed seaweed has the potential to accelerate and increase the amount of CO2 drawn down from the atmosphere by seaweed and  to contribute additional powers of carbon sequestration.  This potential is well documented. In this TED Talk given in Edinburgh at the TED Summit in 2019, Tim Flannery explains how farmed seaweed could further help curb global warming. He describes how seaweed can be farmed at massive scale, close to the surface where it grows and then cut and released to fall to the bottom of deeper waters, holding the CO2 within it for hundreds of years. 

​Environmental Risks

Farmed seaweed could be an enormous help in our fight against climate change.  Seaweed already plays an important role in CO2 drawdown.  Farmed seaweed could increase its impact at the same time as forming new products that help lessen our consumption of meat, plastic and fossil fuels. Of course, any interference in natural ecosystems comes with environmental risk. This Frontiers article highlights the need for balancing the potential gain of seaweed farming with the potential risk to the surrounding eco-system, and understanding what dangers might lie in the expansion of seaweed farming to an industrial scale.  By understanding the dangers, we can ensure that the benefits of seaweed farming far outweigh any collateral eco-system damage.. 

To visualise what is involved in the farming of sustainable seaweed, take a look at this short video from the FT (Seaweed: sustainable crop of the future? Dec 2020).  

We strongly recommend viewing both videos and reading the article. It will be 20 minutes of your time well spent. 

David Sheridan is a Director of Green Angel Syndicate, the only angel investment syndicate in the UK specialising in the fight against Climate Change and Global Warming.  For regular updates follow Green Angel Syndicate on LinkedIn and Twitter.