Ocean alkalinity enhancement projects are a carbon-removal project type within the ocean & water segment of the carbon market. They are designed to add alkalinity to seawater so the ocean can absorb and store more atmospheric CO2 as dissolved inorganic carbon. The carbon benefit comes from enhanced atmospheric CO2 uptake by the ocean through alkalinity addition. Common project configurations include Coastal outfall alkalinity enhancement; related seawater-treatment pathways.

The underlying chemistry is promising, but accounting for carbon uptake, dilution, and environmental interactions requires careful scientific design. Ocean-based pathways are developing quickly and can be scientifically compelling, but they generally require especially careful MRV, strong ecological safeguards, and a clear accounting framework for permanence and reversals. For buyers and program designers, the most important diligence questions are: How is air-sea uptake quantified? Are local environmental impacts understood? Are alkalinity delivery, dispersion, and verification robust?