Carbon dioxide consumption and bicarbonate production rates by continental weathering at the LGM and at present-day an update

We construct a range of estimates for the glacial-interglacial variations of CO2 consumption and bicarbonate production rates by continental weathering processes, using two models of continental weathering in conjunction with two data sets for present-day runoff and climate results from four GCMs. Both models consistently produce 25–35% higher global CO2 consumption and 30–40% higher bicarbonate production rates at the LGM than at present-day. In terms of CO2 consumed by silicate weathering, variations calculated here are more than 2.5 times smaller than those derived from the marine Ge/Si record. Areas exposed both now and at the LGM exhibit only little change. The increased bicarbonate production (CO2 consumption) on the continental shelf exposed at the LGM overbalances the decrease due to ice cover by a factor of 3­–4 (resp. 2.3–3.7). However, large uncertainties affect the fluxes in the shelf environment, as shown by sensitivity tests regarding its lithology.