Ocean chemistry at work: Researchers and startups are turning to an approach named ocean alkalinity enhancement to alter seawater chemistry and supercharge its ability to act as a carbon sink while preventing ocean acidification, The Washington Post reported on Friday.

Why is this beneficial? Oceans already absorb vast amounts of CO2 all the time, reacting with natural alkaline substances such as limestone and other rocks to form bicarbonate ions which reduce CO2 without acidifying the ocean. Ocean alkalinity enhancement accelerates this process by introducing acid-neutralizing materials, like crushed or dissolved rocks into the water.

The tech is already in action: Researchers have been exploring this technology for the last five years with early trials showing potential, but scaling remains a challenge. Nova Scotia-based start-up Planetary removed 138 metric tons of carbon last month for Shopify and Stripe. Washington’s Ebb Carbon operates a small site capable of removing up to 100 metric tons annually and has committed in October to remove 350k over the next decade for Microsoft.

But challenges remain: The jury is still out as to how proponents of the tech can actually quantify the amount of carbon sequestered, because alkaline minerals rapidly dissipate in large bodies of water making it difficult to measure the carbon removed.

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