Calcium carbonate dissolution rate changes under future climate scenarios

Abstract. Calcium carbonate is known to be dissolving throughout various portions of the water column, but little is known about how this will change in the future. Model output of a large range of climate scenarios and an established diagnostic approach are used to understand the future of calcium carbonate dissolution rates. Changes in ocean salinity and mean age are of leading order importance to future calcium carbonate dissolution rates. The calcium carbonate dissolution rates can range by an order of magnitude across climate scenarios in regions such as the subtropical Atlantic Ocean basins. Some geoengineering methods are more effective than others at decreasing calcium carbonate dissolution rates in particular regions of the ocean; however, no single technique is effective everywhere. Altered calcium carbonate dissolution rates have implications for the physical ocean state projections, such as those for sea level, which are discussed in terms of direct and indirect impacts. Direct impacts due to the presence of suspended sediments comprised of calcium carbonate can be significant in some river deltas and nearby coasts.