“IF you take one square metre of seaweed, of kelp forest, it will capture five times more carbon than any land forest,” says visionary marine geologist Pierre Erwes.

The kelp plant, whose floating ribbons we often see wafting at the ocean’s edge, is extremely efficient at “drawing down” CO2 from the atmosphere. That is why the survival of kelp forests is so crucial – to hit our carbon targets we need to both reduce our emissions and draw down those already out there. It’s also why kelp is as the heart of a growing push towards what is being called the blue economy.

Erwes is one of many international and local speakers gathering in Oban on February 18 for a Scottish Seaweed Industry Association conference titled Kickstarting The Seaweed Economy. He and others will create a conversation over seaweed in a seemingly new language, a lexicon of blue that includes terms like blue economy, blue new deal, blue co-ops, blue carbon and blue biotech.

It will be about how Scotland can create jobs in rural communities, manufacture revolutionary products and combat climate change at the same time. In Erwes’ view, seaweed is “one of the key elements on Earth – we are just approaching the potential of this amazing organism”.

In Scotland, we have a history with kelp. We have long harvested it and other seaweed for many purposes, burning it to create soda ash, extracting iodine from it, and producing alginates. Though the industry has for many years been dormant, the seaweed harvest and processing once helped sustain communities on the west coast and in the Hebrides and Orkney Islands. And now, in this age of climate emergency, some are looking to it once more as a crop.

But this isn’t about harvesting wild kelp – this is about cultivation. It’s about putting down ropes, seeding them, letting the kelp grow, then harvesting with minimum impact. In Erwes’ view it’s about more net kelp in the ocean, not less.

As he puts it: “We want to expand the forest so we can have more harvesting. In Scotland, policymakers should consider this. It’s not only the question of the amount of kelp we are going to take, but it’s also for the next 20 years the amount we’re going to plant and replant.”

Already, globally, seaweed aquaculture is a huge industry, though 95% of it is farmed in southeast Asia. Other countries in Europe – the Faroes, Iceland, Norway, Denmark, the Netherlands, Ireland – have a growing industry. But, says Lawrie Stove, managing director of AquaMoor which creates innovative structures for seaweed farms, “Scotland is one of the last ones to get going, though we have a superb latent capacity for seaweed farming”.

A recent report into the potential of seaweed farming commissioned by Argyll and Bute Council stated that “the development of a seaweed cultivation industry would provide important economic growth to the Highlands and Islands”.

“Until now, the focus here has been on academic research and there’s a lot of money available for research but little available for stimulating commercial activity,” Stove says. “That’s why we need to focus on the blue economy and bringing blue investors in. There’s a desire and a want to farm seaweed, an understanding it should be part of Scotland’s blue economy, and it’s coming together.”

Stove describes this type of seaweed farming, with kelp growing from ropes in the sea, as “restorative aquaculture”. “There’s an ecological enhancement from farming seaweed in the sea – there’s no fertilisers, no chemicals, no freshwater, no detrimental ecological effects.”

Not only can seaweed provide a carbon sink, there are also other benefits, he says. “It can absorb nitrates and it can help towards deacidification of the oceans, by the nutrient uptake that it involves,” Stove points out. “And it can attenuate wave energy and help protect coastal communities.

“Benefits also include the ecological enhancement to any body of water, creating an area that is really good for fish, like a nursery ground, and the creation of valuable jobs in coastal communities.”

Though this model is called aquaculture, it is little like Scotland’s major aquaculture industry, salmon farming. Fiona Houston, founder of Mara Seaweed, which sells seasonings and salt replacements, describes it as “more like ranching”.

“It’s putting some ropes in the sea and the seaweed grows,” she says.

Houston is a key force in driving the idea that Scotland needs to rapidly grow a “blue economy”. Since she started Mara Seaweed, a product now stocked in Tesco, she has been driven by the idea that Scotland could develop a significant industry around seaweed.

“I spotted that consumers were more interested in where food was coming from,” says Houston. “I was also aware that in Asia seaweed is eaten on a daily basis. I thought this is crazy. We’ve got 11,000km of coastline in Scotland. We’ve got a resource that is vastly undervalued. And if we used it in the past and it’s got a role in the modern diet, why aren’t we doing it?”

To begin with, Houston wasn’t thinking about seaweed as an element in the fight against climate change. That came later when she learned that seaweed was more efficient at capturing carbon than the rainforest.

“Seaweed is not only good for you and tastes good, it’s good for the planet,” she says. “This is not now about just the value of seaweed as a product. It’s the value it has for carbon capture.

“There’s a need for the growth of aquaculture beyond the commercial growth. If we could get a bluegreen deal going that would be great.”

The model Houston and others are advocating is small-scale farming by local communities. One of the things she hopes to do is make Scotland part of an international blue-cooperative of sustainable seaweed farmers being developed by Erwes. “It’s about how you create sustainable employment in geographically remote areas – and for public policymakers that is a really key issue,” she says.

Professor Michele Stanley has been researching seaweed cultivation at the Scottish Association for Marine Science (SAMS), which runs two test farms off the west coast of Scotland. Stanley is involved in ongoing research into the environmental impact of farming. “It’s how you manage it,” she points out. “It’s choosing the right site and size of farm – and making sure there’s enough nutrients in the water to support the growth, and that you’re then not going to impact on other organisms around.”

One of the things she has been doing is looking at how seaweed farming might benefit sealife in the area. SAMS is working with a Chinese partner that has already shown that when shellfish are grown with seaweed there is a positive impact on them. “One of the problems is that the pH of the ocean has been increasing because of the CO2 dissolving, and that destroys the shells of the shellfish,” says Stanley. “If you’re growing it with seaweed, it is taking CO2 out and putting oxygen in.”

According to Stanley, there is a fascinating range of possibilities around products from seaweed. “There are seaweeds that have the potential for anti-inflammatory compounds, antimicrobial compounds. Scotland has a long seaweed history which waned and now you’ve got renewed interest in it. Among the old journals we have at SAMS from the 1950s there’s a copy from a meeting which was looking at using parts of seaweed for textile production.”

One promising product being developed using brown kelp in Scotland is a biopackaging material that could provide a biodegradable alternative to plastic on food packaging. It is, says Dr Charles Bavington, a biochemist and founder of Oban-based start-up Oceanium, “a completely compostable, ocean-safe packaging material”.

Bavington began this journey into seaweed packaging after he came in contact with Oceanium co-founder Karen Scofield Seal, a business woman who had studied sustainability and, he says, “got really excited about the potential of seaweed for solving a lot of climate problems”.

They now use the “whole plant” from which they make packaging material, food products, an anti-inflammatory called fucoidan, and beta-glucan, a nutraceutical used for cardiovascular health, and water, which will be reused in processing.

Oceanium uses only sustainably farmed seaweed. “We don’t take wild harvest, because it wouldn’t be sustainable for the kind of volumes we’re going to need,” says Bavington. “But having large-scale sustainably farmed seaweed is something that isn’t available in the Western world.”

Like many of those working in the field, he is keen that the growth of seaweed farming is approached with care for environmental impact. “We need to be careful, because there can be unintended consequences of anything, and for what we’re proposing to work, it has to be at large scale. We need to be really careful and check before we go for huge scale that we’ve considered all the unintended consequences of very large-scale seaweed farming and processing.”

But some warn that when it comes to kelp, farming it is not where are priorities should be. David Reay, professor of carbon management at the University of Edinburgh, says: “I’d be deeply cautious about seaweed ‘farming’ to tackle climate change – we know we have huge so-called ‘blue carbon’ stocks in the seaweed and sediments around Scotland, but these are also vital ecosystems that provide a habitat for myriad species and help to buffer us from the worst impacts of storm surges and rising sea levels.

“Yes, we need to improve our understanding of these marine systems and the ways in which they gain and lose carbon, but at this stage it should be more about better protecting these precious ecosystems rather than trying to farm them.”

There is a balance to be struck. Seaweed is Scotland’s forgotten treasure. What counts most that it remains, or even expands as a “blue carbon” sink. Kelp clearly matters.