The mass of CO₂ captured through alkaline feedstock weathering and carbonate mineralization can be quantified by measuring CO₂ loss from air (e.g. using eddy covariance flux towers or dynamic closed chambers), measurement of carbonate chemistry parameters (e.g. pH, TA, or DIC), or measuring changes in mineral content. If measuring changes in mineral content, it is critical to carefully characterize the starting carbonate content and variability of the feedstock. It is likely that a combination of quantification approaches will be needed to bound outcomes. Calibrated reactive transport models may also play a role in estimating long-term trends of CO₂ uptake. Measurement and modeling approaches must take into account the potential for short-term cycles of absorption and outgassing.