Understanding rates of carbon dioxide removal through ocean alkalinity enhancement

At a time when removing carbon dioxide from the atmosphere is urgently needed to halt and reverse climate change, an interdisciplinary team is working to leverage the ocean’s ability to serve as a natural carbon sink. Led by Matthew Kanan, associate professor of chemistry and director of the TomKat Center for Sustainable Energy, and Rob Dunbar, professor of oceans and of Earth system science and senior fellow at the Stanford Woods Institute for the Environment, the team will assess various ways of adding alkaline substances to seawater to promote the transfer of carbon dioxide from the air into the ocean. They will measure how adding magnesium hydroxide (a compound that can be produced synthetically from abundant rocks) to seawater, freshwater, and brines affects the rate of carbon dioxide uptake. In addition to potentially removing carbon dioxide, adding alkaline substances like magnesium hydroxide to oceans can make them less acidic, helping calcifying organisms such as corals and bivalves maintain their shells and skeletons. Their research will assess how adding large amounts of alkaline substances impacts the ocean and whether this approach can be scaled safely to sequester more carbon dioxide.