Climate change effects at basin-scale: Weathering rates and CO2 consumption assessment by using the reaction path modelling

Reaction Path Modelling was used to calculate the fluxes in terms of solutes and CO2 consumption during the water-rock interaction process at the basin-scale, considering the current and future climate scenarios (temperature and atmospheric CO2 concentration) and two types of solid reagent (Silicate Solid Reagent-SSR and Carbonate-Silicate Reagent C-SSR). Two modelling were performed considering solid reagents and simulating their weathering in the current climate scenario and two other simulations were developed to consider the future climate scenario (Representative Concentration Pathways – RCP 8.5). The study highlights that although the higher temperature promotes an increase of total dissolved ions (TDS) into riverine waters, the higher temperature also causes a decrease in precipitation and, thus, in the runoff. This condition will lead to a reduction in weathering rate and CO2 consumption at the basin scale. The main indirect effect of a negative CO2 consumption budget is a further increase in CO2 atmospheric concentration.