Seaweed, previously the unwanted guest at your beach party, is now increasingly associated with sushi, superfoods, spa treatments and – amongst scientists, at least – solutions to climate change.

So just how, exactly, can seaweed help us tackle the climate crisis?

Increased carbon dioxide in the atmosphere, mostly due to fossil fuel combustion, is driving rapid climate change. As the atmospheric carbon dioxide goes up, so too does the carbon dioxide in the oceans.

We know that we need to stop burning fossil fuels, fast. But we also need to remove some of the carbon dioxide that’s already in the air and oceans.

And that’s where seaweed comes in.

Like other plants, as seaweed grows it absorbs carbon dioxide. But what makes seaweed a particularly appealing carbon sink is its growth rate: about 30 to 60 times the rate of land-based plants. This rapid turnover rate makes it ideal for mass scale production.

On top of this, some species of seaweed are super stable and don’t break down easily, meaning they have high potential for long-term carbon storage. Plus, seaweed can also be harvested and used to produce biofuels, reducing our need for fossil fuels.

What’s the potential?

Researchers have estimated that if 9% of the world’s ocean surface were used for seaweed farming, we would be removing 53 billion tonnes of CO₂ from the atmosphere. And that’s just from the absorption of carbon during the growing process!

If that seaweed was then harvested and processed, it could also produce enough biofuels to replace ALL of today’s fossil fuel energy needs. The nutrients left over from this process could then be recycled to assist with further seaweed farming.

And it doesn’t stop there. Seaweed farming can also produce safe sites for breeding fish populations, as well as reversing ocean acidification.

So what’s the hold up?

The technology that’s needed to achieve this level of global seaweed farming is already available and in use, however at much smaller scales. Seaweed farming is well established in Asia, and China is leading the way with hundreds of square kilometres of seaweed farms off its coast.

The technology is slowly expanding into other regions, but there aren’t any offshore sites in Australia… yet!

If seaweed can remove carbon dioxide from the atmosphere, AND also reduce fossil fuel dependency by providing a sustainable source of biofuels, we definitely hope to see more of it in the future.

Image credit: Flickr user Bjørn Christian Tørrissen icensed under CC BY-NC 2.0