Is Seaweed The Revolutionary Ingredient The World Has Been Waiting For?

What’s arguably the greatest untapped resource on this planet; one which could help save the climate, restore biodiversity and feed the world without land, fresh water or chemicals? Yes, it’s seaweed – already 10% of the diet in Japan, and an incredible source of scarce nutrients such as vitamin B12, as well as protein and essential fats.

Seaweed is badly named, however, according to Vincent Doumeizel, senior advisor on oceans to the UN Global Compact. “We should call them sea vegetables so people can understand how delicious they are; we should call them sea forests so people can understand we need to protect them,” Doumeizel says with near messianic fervour.

The ocean covers 70% of the world’s surface and yet contributes less than 2% to the calories in the human food system. Land-based agriculture – farming, as we call it – is the biggest driver of biodiversity destruction worldwide due to habitat loss of wildlife and contributes a quarter of global greenhouse gas emissions. If we produced more of our food in the ocean, the resulting seaweed farms could help to reduce fertiliser pollution washing off the land as well as sequestering carbon and acting as nurseries to fish. 

Seaweed farming is not hypothetical: it is already carried out in 56 countries worldwide, although 99% of farmed seaweed is produced in Asia. Methods can be fairly rudimentary – seaweeds are grown on lines or ropes attached to stakes or platforms anchored to the seabed and hauled up on boats for harvesting. It is environmentally friendly so long as seaweed farmers do not excessively disturb the ocean bed or cut down coastal mangroves. 

And the promise of seaweed doesn’t stop at food. Its fibres could replace cotton, which requires startling volumes of fresh water and chemicals to produce. With seaweed, cellulose is dissolved out of the harvested material and spun to create fibres that are then used to produce cloth. While much conventional clothing releases microplastic fibres that accumulate in rivers, soils and even our own bodies, seaweed fibres are fully biodegradable. It’s an idea that is catching on: the Italian-Japanese fashion designer Leticia Credidio uses seaweed in her new Ocean collection. 

Seaweed is now hitting the big time. Thanks partly to the efforts of Doumeizel, seaweed has come to the attention of the United Nations, which now promotes it as a way to help meet the Sustainable Development Goals (SDGs). Nine of the 17 SDGs – from the goal of no hunger to gender equality (women tend to especially benefit in coastal communities cultivating seaweed) – are thought to be advanced by seaweed development. 

Managed right, seaweed can be restorative for the oceans, good for our health and help wean us off our addiction to plastics. No wonder they call it a revolution.

Here are five fascinating facts about seaweed you need to have on your radar:

1. A small amount of red seaweed added to animal feeds can reduce methane emissions from cows by 82%, helping offset global warming.
2. Seaweeds are the only ‘vegetable’ source of vitamin B12 and omega-3 fatty acids, which are essential for good health.
3. Plastics produced from seaweed can not only be biodegradable but also edible.
4. Seaweed can have diverse medical benefits, with anti-bacterial, anti-inflammatory, and analgesic properties in both raw and cooked forms.
5. Seaweed cultivation requires very little high-tech investment: it can easily be carried out in developing countries with accessible materials such as ropes and wooden poles.

Mark Lynas is an author and campaigner based in Wales. He is climate advisor to former president of the Maldives Mohamed Nasheed, and his latest book is Our Final Warning: Six Degrees Of Climate Emergency