The efficacy of enhancing carbonate weathering for carbon dioxide sequestration

ABSTRACT: Enhanced weathering is a geoengineering strategy aiming to increase continental weathering rates, thereby increasing the delivery of atmospheric carbon (as HCO−3) to the oceans. Most enhanced weathering studies focus on the capacity of silicate rocks (e.g., basalt) and minerals (e.g., olivine, Mg2SiO4, or wollastonite CaSiO3) to remove atmospheric CO2. However, carbonate minerals (e.g., calcite, CaCO3) could provide an additional, rapid way to increase HCO−3 export to the oceans. Recent studies suggest that 0.84 Gt C yr−1could be removed from the atmosphere through the enhanced dissolution of calcite in soils, provided carbonic acid ...