🔬Research StageCarbon Management • Nature-based Solutions

Seaweed Carbon Farming

Seaweed carbon farming cultivates macroalgae in open ocean environments to sequester atmospheric CO₂, with potential to remove 1-10 gigatons of CO₂ annually if deployed at scale. Seaweed farms can sequester 20-35 tons of CO₂ per hectare annually while producing biomass for food, feed, and biofuels. Companies like Climate Foundation and Running Tide are developing systems with costs targeting $50-150 per ton of CO₂ removed.

How It Works

Large-scale seaweed cultivation uses submerged rope or mesh systems anchored to the ocean floor or floating platforms. Fast-growing seaweed species like kelp absorb dissolved CO₂ from seawater during photosynthesis. Harvested biomass can be processed into products or sunk to deep ocean for permanent carbon storage. Ocean upwelling and current systems provide nutrients and optimize growing conditions.

Advantages

Provides massive carbon sequestration potential using abundant ocean space, produces valuable biomass for food, feed, and industrial applications, and improves ocean health by reducing acidification. Seaweed farming requires no freshwater, fertilizer, or pesticides. The technology creates blue economy opportunities for coastal communities.

Challenges

Unproven at large scale with uncertain environmental impacts, faces significant technical challenges for open ocean cultivation, and requires new governance frameworks for ocean use. Carbon permanence depends on deep ocean storage or utilization pathways. Potential conflicts with shipping, fishing, and marine protected areas.