It is one of several “carbon removal” techniques that help address climate change by drawing down CO2, the most important climate-warming greenhouse gas humans are adding to the atmosphere.
Extending a natural process
The ocean already absorbs around 25% of the CO2 humans add to the atmosphere—an astonishing 2.8 billion tons of carbon each year.1
This absorption happens through chemical reactions between air and seawater at the ocean surface. When CO2 enters the ocean, it reacts with water to form carbonic acid. Like all acids, this carbonic acid gives off hydrogen ions, which react with other, “alkaline” molecules in the water that can receive those ions. In the end, the carbon from the CO2 forms stable bicarbonate and carbonate ions.
This has the benefit of slowing climate change. However, it also makes the ocean more acidic, with dangerous consequences for marine life. A more acidic ocean also gradually loses its ability to keep absorbing CO2 from the atmosphere. Hence, if we could make the ocean more alkaline, we could increase the “CO2 capacity” of the ocean, further slow climate change, and reverse some of the harmful ocean acidification caused by our CO2 emissions.2
Alkalinity enhancement
Natural ocean alkalinity is driven by alkaline minerals, such as calcium carbonate, found in shells of microbes, corals and shellfish. Some rocks, such as olivine and basalt, also contribute to ocean alkalinity. As these minerals dissolve in seawater, they give off the alkaline ions that let the ocean absorb CO2.
Para leer más ingrese a:
https://climate.mit.edu/explainers/ocean-alkalinity-enhancement