Removing Carbon Dioxide Through Seaweed Cultivation: Legal Challenges and Opportunities

Scientists increasingly agree that carbon dioxide removal will be needed, alongside deep emissions cuts, to stave off the worst impacts of climate change. A wide variety of technologies and strategies have been proposed to remove carbon dioxide from the atmosphere. To date, most research has focused on terrestrial-based approaches, but they often have large land requirements, and may present other risks and challenges. As such, there is growing interest in using the oceans, which have already absorbed more than a quarter of anthropogenic carbon dioxide emissions, and could become an even larger carbon sink in the future. This paper explores the ocean-based carbon dioxide removal strategy of seaweed cultivation. Seaweed cultivation involves the growing of kelp and other macroalgae to store carbon in biomass, which can then either be used to replace more greenhouse gas-intensive products or sequestered by sinking the seaweed. Seaweed is typically grown in coastal waters near shore, but research is investigating the possibility of cultivation further offshore, including on the high seas, and sequestration in the deep sea. This paper examines the international and U.S. legal frameworks that apply to seaweed cultivation. Subsequent work will examine the relevant laws of selected other coastal countries