Packaging made from seaweed can help solve our plastics problem, but not if we rush it.
Russell Reed is an interdisciplinary environmentalist dedicated to building a more inclusive environmental movement. He is a founding member of Sway, a company building seaweed-based replacements for plastic packaging, where he serves as the partnerships and impact lead.
In the world of climate solutions, seaweed has been making waves. From sea-veggie burgers and methane-reducing cattle feed to textiles and dyes, seaweed — the predecessor of all land plants, and cultivated at a relatively small scale for centuries — is a promising resource for innovators in a surprising range of industries. Investments in startups working with it doubled in 2021. Five of the eight finalists for this year’s Tom Ford Plastic Innovation Prize (including our company, Sway) are using it to develop rapidly degradable replacements for petroleum-based plastic packaging.
It’s an exciting time to be an innovator working in this space, where it feels like a seaweed renaissance is emerging. But I see a concerning phenomenon in the industry’s investment trends. The largest number of deals are being made for applications like ours, which purchase seaweed for use in innovative products. This means less venture capital is reaching companies involved in other stages of product development, including farming, processing, infrastructure, and conservation.
While companies like ours have an important role to play in expanding demand for seaweed, which many believe has great potential as a climate solution, these products will not exist if our industry does not pay equal attention to scientific research, regulations, and stakeholder coalition-building. We run the risk of falling short on the very social and ecological benefits that sit at the heart of our mission.
While companies like ours have an important role to play in expanding demand for seaweed, we run the risk of falling short on the very social and ecological benefits at the heart of our mission.
In the race to build high-performance, scalable, and rapidly degradable replacements for plastic packaging, seaweed stands out from other feedstocks like corn and soy. It is abundant and diverse, with more than 12,000 species growing on virtually every coastline in the world. These hardy macroalgae have long been used in food and cosmetics industries due to their high concentration of hydrocolloids — agar, alginate, or carrageenan, depending on the species — which act as valuable gelling agents in a wide range of products. We are developing a competitive alternative to petroleum-based plastic packaging, offering products like shopping bags, food packets, and mailers that will compost in weeks rather than persist for centuries.
But our motivation — and, I reckon, the enthusiasm we have received from investors, customers, and the media — also stems from the potential climate solution that ocean-farming presents. Seaweed processes large amounts of carbon. Some species can store up to 20 times more CO₂ than land crops, and what’s shed onto the ocean floor can create long-term sequestration. Plus, growing it does not rely on arable land, fresh water, or fertilizer to grow, which makes seaweed less carbon-intensive than land crops.
Marine seaweed farms have been shown to combat deadly ocean acidification and provide habitats and breeding grounds for biodiverse life. Cultivation can also bring much-needed transitional economic opportunities for coastal communities bearing the brunt of climate change and decades of overfishing — from lobster fishermen in Maine to Indigenous communities from Alaska to Colombia. The growth of local seaweed economies can not only provide predictable and dignified employment, but in doing so can also curb hunting of protected species like sea turtles and sharks.
But the growth of a thriving, regenerative seaweed economy is not inevitable. Without close attention to its ecological impact, seaweed cultivation can bring negative results like marine eutrophication, which depletes ocean waters of nutrients; diseases that can spread to wild seaweed populations; and genetic alterations caused by monocropping. As in any industry, the prominence of “middle men” and monopoly groups can also reduce the economic benefits to coastal communities. Farmers can confront these threats, even on operations of substantial scale, through marine planning guided by local ecological knowledge and scientific research.
To foster the growth of regenerative ocean farming and unlock the true potential of seaweed cultivation as a climate solution, investors need to distribute funds throughout the value chain. We need only look to the carbon market to see how nature-based solutions driven by economic demand can turn unsustainable; perverse market incentives have sometimes driven deforestation. And yet we already see similar dynamics in the seaweed-for-blue-carbon market — scientists have raised concerns over practices like the use of fertilizers to scale cultivation, which can damage surrounding ocean ecosystems.
For seaweed to fuel solutions at the scale of the plastics problem, as well as in food, fashion, and animal agriculture, production must increase. But we must ensure that it will also increase sustainably, prioritizing the social and ecological benefits we wish to realize.
First, we need more research. Virtually any scientific publication on seaweed cultivation includes a laundry list of data gaps and further research questions, suggesting that excitement around seaweed’s climate potential may be running ahead of the evidence. In order to pursue this solution sustainably, we must have a robust understanding of its ecological risks and benefits as well as best practices.
Once we have this knowledge, we must set clear standards for regenerative ocean farming and integrate seaweed farms into marine planning in a way that promotes conservation and respects ecological limitations and carrying capacities.
Second, we need proper regulation. While Maine has led the way on ecologically driven regulation in the United States, offering a comprehensive but robust permitting process, other states have not. People often joke that in California, for example, one can more readily obtain a permit to drill offshore oil than to plant a seaweed farm. Guided by science, regulators must ensure that seaweed economies can grow — and grow responsibly.
Finally, we need community. One of my peers in regenerative land agriculture recently referred to that industry as a “loud room,” with an abundance of conflicting research, lively debate, and competing visions for the future of the field. By comparison, regenerative ocean farming is quiet, lacking in meaningful engagement between product innovators, farmers, regulators, conservation organizations, researchers, and seaweed’s many other stakeholders. Through community — including all the debate and disagreement that comes with it — we will work toward a shared vision of seaweed aquaculture and an agenda to actualize that vision.
The history of plastic serves as a cautionary tale of good intentions marred by unchecked demand. In 1863, John Wesley Hyatt invented the first known plastic in response to a call for replacements for the traditional billiard ball, which had placed great strain on elephant populations by increasing demand for ivory. Hyatt’s replacement was made from wood and natural shellac, but it soon led to the creation of the first petroleum-derived plastic.
That shift — made to accommodate peaking demand for cheap consumer goods — marked the beginning of the plastic crisis we are in today. Seaweed is a promising solution. To see it through, industry innovators must stand against the long history of market-driven ecological crises and take responsibility for helping forge a regenerative future for seaweed.