The growing role of seaweed in climate action: a natural solution

Seaweed farming has become a promising solution in the fight against climate change. As one of the fastest-growing sectors in global food production, seaweed aquaculture offers a set of benefits that could significantly contribute to climate change mitigation and adaptation. By acting as a carbon sink, supporting biodiversity, protecting coastlines, and improving water quality, seaweed farming is gaining recognition as an innovative approach to environmental challenges. But can this underwater industry truly make a meaningful difference in the battle against climate change?

What is driving interest in seaweed aquaculture?

The seaweed aquaculture industry has grown significantly, with production tripling between 2000 and 2019. This growth is due to the increasing variety of seaweed uses, from food and medicine to cosmetics, animal feed, and biofuels. The U.S. government is also funding research on seaweed as a biofuel source.

The growing interest in seaweed extends beyond its commercial value. Many seaweed species grow faster than land plants and don’t require freshwater or arable land. This makes seaweed an appealing alternative to traditional crops, especially with global concerns over food security. Seaweed also helps reduce water pollution by absorbing dissolved nutrients from agricultural runoff, which can harm aquatic ecosystems. Furthermore, as seaweed grows, it absorbs carbon from both the ocean and the atmosphere. If seaweed is sunk into deep water instead of being harvested, it offers a way to sequester carbon, reducing greenhouse gases.

The market demand for sustainable products has further increased seaweed’s appeal.

What is seaweed?

Seaweed refers to large, multicellular algae that grow in marine environments. Unlike microalgae, seaweed can be classified into three main groups based on color: green, red, and brown. There are thousands of species, but only a few are farmed commercially. As interest in seaweed rises, it is now being called “sea vegetables” to highlight its potential as a food source.

Can seaweed help fight climate change?

Seaweed may be an unexpected solution to climate change. It absorbs carbon dioxide (CO2), helping to cool both the oceans and the planet. By capturing greenhouse gases, seaweed naturally defends against climate change.

Seaweed is versatile and used in many products, from toothpaste to lotions and textiles. It is one of the most resource-efficient crops, needing no land, fertilizer, or freshwater to grow. Unlike traditional farming, seaweed farming takes place in the ocean, where seedlings grow on ropes, using sunlight and nutrients from the water. Some species, like giant kelp.

Seaweed also provides health benefits. It is rich in vitamins K and B12, antioxidants, and fiber. By replacing carbon-intensive materials with seaweed, we can reduce our environmental footprint. Additionally, adding small amounts of seaweed to livestock feed has been shown to reduce methane emissions, improving cattle health while reducing greenhouse gases.

For coastal communities, seaweed farming offers a new economic opportunity. As traditional fisheries decline, seaweed farming can provide a viable source of income. In fact, some Maine lobstermen earned more from farming seaweed than from their lobster catch last year.

The role of seaweed farming in climate change mitigation

Seaweed farms act as carbon sinks, absorbing CO2 from the atmosphere. As seaweed grows, it sequesters carbon, some of which is stored in ocean sediments or transported to deep waters. Experts estimate seaweed farming could sequester around 1,500 tons of CO2 per square kilometer annually, equivalent to the carbon emissions avoided from burning fossil fuels.

In addition to sequestering carbon, seaweed farming can help reduce emissions in other sectors. Seaweed can be processed into biofuels, decreasing reliance on fossil fuels. It can also replace synthetic fertilizers in agriculture, which contribute to greenhouse gas emissions. When added to livestock feed, seaweed significantly reduces methane emissions from cattle.

However, challenges remain. Limited coastal space and competition from industries like shipping and tourism make it difficult to establish large-scale seaweed farms. Offshore conditions also require advanced technology, limiting the potential for expansion in certain regions.

Climate change adaptation: how seaweed farming helps

Seaweed farming offers important benefits for adapting to climate change, especially for coastal communities threatened by rising sea levels, storms, and ocean acidification.

1. Coastal Protection: Seaweed farms act as buffers, absorbing wave energy and protecting coastlines from erosion. In some cases, seaweed can reduce wave heights by 60%, providing natural coastal protection. However, during extreme weather events, seaweed farms may suffer damage.

2. Ocean Acidification and Deoxygenation: Seaweed farms can help counter ocean acidification by raising local pH levels, creating a more favorable environment for marine life. Seaweed farms also produce oxygen through photosynthesis, helping mitigate ocean deoxygenation, a result of climate change.

3. Biodiversity Support: Seaweed farms promote biodiversity by creating habitats for marine species, including fish and crabs. However, these ecosystems are temporary and depend on the proper management of farms.

The potential for expanding seaweed farming

Seaweed farming holds considerable promise, but several challenges need addressing to expand the industry. Suitable coastal areas for farming are limited, and competition from other industries complicates efforts to establish large-scale farms. Additionally, seaweed farming requires specific conditions, such as clean water and proper nutrient levels, meaning careful spatial planning is essential.

To maximize the climate benefits of seaweed farming, policies, technological innovations, and market development are key. Combining seaweed farming with renewable energy or co-locating farms with other marine industries could help reduce the carbon footprint of the industry. Furthermore, promoting markets for seaweed-based products can ensure economic sustainability and incentivize farmers to engage in climate change mitigation and adaptation.

Conclusion

Seaweed farming offers a promising, underutilized solution for both climate change mitigation and adaptation. As a natural carbon sink, seaweed can sequester CO2 while providing ecological benefits, such as coastal protection, habitat for marine life, and improved water quality. Despite challenges like limited coastal space and the need for advanced technology, seaweed farming can contribute significantly to climate change strategies. By supporting policies that encourage seaweed farming, we can harness the power of this natural resource to protect coastal communities, mitigate climate change, and provide economic opportunities for coastal populations.