Ocean Alkalinity Enhancement represents a nature-inspired approach to carbon dioxide removal that mimics and accelerates the Earth's natural carbon cycle. The technology centres on the controlled dispersal of finely ground alkaline minerals—primarily olivine, limestone, or similar silicate and carbonate rocks—into marine environments. When these minerals dissolve in seawater, they release alkalinity in the form of bicarbonate and carbonate ions, which react with dissolved carbon dioxide to form stable compounds that can remain sequestered in the ocean for thousands to hundreds of thousands of years. The process essentially speeds up the geological weathering that naturally occurs over millennia, transforming atmospheric CO2 into dissolved inorganic carbon that becomes part of the ocean's vast carbon reservoir. Deployment methods vary from ship-based dispersal systems that grind and distribute minerals across targeted ocean areas to coastal installations that process minerals through wave action or tidal flows, and even beach nourishment projects using olivine sand.
This approach addresses two interconnected planetary challenges: the urgent need for scalable carbon dioxide removal and the growing crisis of ocean acidification. As oceans absorb approximately one-quarter of human-generated CO2 emissions, they become more acidic, threatening marine ecosystems from coral reefs to shellfish populations. Ocean Alkalinity Enhancement simultaneously removes additional CO2 from the atmosphere while raising seawater pH, effectively countering acidification in treated areas. Unlike point-source carbon capture technologies that require extensive infrastructure and energy inputs, this method leverages the ocean's natural chemistry and vast surface area. The permanence of carbon storage—measured in geological timescales rather than decades—distinguishes it from biological sequestration approaches that face risks of reversal through decomposition or disturbance. Early research suggests that the process may also provide co-benefits for marine ecosystems under climate stress, potentially supporting calcifying organisms like corals and mollusks that struggle in acidifying waters.
Several pilot programs and research initiatives are currently exploring the feasibility and environmental impacts of Ocean Alkalinity Enhancement at various scales. Coastal demonstration projects have tested olivine dispersal in beach environments, while research vessels have conducted controlled experiments measuring alkalinity changes and biological responses in open ocean settings. The technology faces important questions around optimal mineral selection, grinding energy requirements, dispersal methodologies, and comprehensive environmental monitoring to ensure no unintended ecological consequences. Regulatory frameworks for marine carbon dioxide removal are still emerging, with international bodies working to establish guidelines that balance climate intervention needs with ocean protection. As the climate crisis intensifies and nations seek portfolio approaches to carbon removal, Ocean Alkalinity Enhancement is gaining recognition as a potentially scalable solution that works with natural systems rather than against them, offering a pathway to address both atmospheric carbon accumulation and ocean health in an integrated manner.
