Is large-scale ocean alkalinization a feasible strategy for mitigating ocean acidification?

If carbon emissions keep increasing unabated over the next century, atmospheric carbon dioxide concentrations will reach levels that are probably unprecedented during the past 30 million years. As a major sink for anthropogenic carbon dioxide, the world ocean is already acidifying, resulting in a lowering of seawater pH and carbonate mineral saturation state. These parameters are key to calcifying organisms - a decrease in saturation state causes a reduction in the calcification rate of shells and skeletons in many marine organisms. Projections predict an undersatured Arctic Ocean with respect to aragonite minerals within a few decades. The lack of severe reductions in global carbon emissions has prompted exploration of various options to mitigate ocean acidification. One option that is being discussed as a potentially feasible mitigation strategy is the addition of alkaline minerals to the surface ocean, although its viability in terms of costs is yet unclear. In this work, we present numerical simulations using the LOSCAR model (Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model) to assess the consequences for and evolution of ocean carbonate chemistry and atmospheric CO2 if a large-scale program of ocean alkalinization was put into place within the next decade and was run over the next 400 years.