Although the oceans are warming about 40% faster than the UN had previously predicted, the World Resources Institute published a report in 2019, imagining the ocean as a powerful source of solutions. One of many solutions, championed by Bren Smith, co-founder of GreenWave, sees kelp farming as a way to both restore our oceans and feed the planet. He points out that seaweed harvesting once was a major industry in the United States. In the early 1900s, 1,500 workers produced 52 different products from kelp on the docks of San Diego.
Seaweed forests currently provide vital ecosystem services with an estimated $500 billion dollar value, absorbing pollution and sequestering carbon. Seaweed-based biofuel, animal feed, fertilizer and bioplastics are some products showing promise for decarbonizing industries.
Seaweed plays many important roles in coastal ecosystems. Seaweed provides food and habitat for other marine species, cleans coastal waters by removing excess nutrients from runoff, and absorbs carbon dioxide from the water which protects shelled animals (like oysters) from ocean acidification.
A 2019 California study has shown that integrating a certain kind of red algae seaweed into cows’ diets can reduce methane emissions by more than 50 percent. Since dairy cows are responsible for the majority of the state’s methane emissions, methane-reducing seaweed is a promising solution.
Because seaweed grows in the winter, fishermen can harvest it during their slow season to diversify their income. This seaweed farming—or seaweed aquaculture—provides an opportunity for fishermen to continue making a living as fisheries sectors face impacts from climate change.
Farmed seaweed is also an ingredient in cosmetics, medicine, human foods and fertilizer. Seaweed farms absorb nutrients and carbon dioxide to grow. The farms can help improve water quality and buffer the effects of ocean acidification in surrounding areas.
A 2023 study found that seaweed forests play a major role in carbon sequestration, helping keep about “36 million metric tons of carbon out of the atmosphere.”
These same seaweed forests are at risk due to climate change, with rising temperatures and pollution threatening their populations.
CREDIT: NOAA
