A 2023 study found that olivine sand deployed across the oceans would mostly sink into the depths before it could raise pH. Yool and Palmiéri modelled an alternative scenario, in which the olivine would be spread over coastal shelves less than 100 metres deep to keep it close to the surface. The study found that currents would then redistribute the more alkaline water, with half of atmospheric CO2 absorption happening off the shelves. Alkalinity would increase most in shallow, warm seas like the Yellow Sea, Gulf of Mexico and Persian Gulf and around the Indonesian and Malaysian archipelagos. "Those would be regions where I would be starting to think: what are they like ecologically and would they be able to tolerate this sort of perturbation?" says Yool.