An Integrated Modelling Framework to Determine Terrestrial Carbon Dioxide Removal via Enhanced Rock Weathering

Enhanced rock weathering (ERW) is an emerging carbon dioxide removal (CDR) strategy that can support net-zero emission targets. However, current ERW modelling efforts rely on assumptions that introduce substantial variation in CDR estimates across varying ecosystems and hydroclimatic conditions. They typically ignore or oversimplify plant–soil interactions and high-frequency hydrological dynamics, obscuring short-term weathering responses and biotic feedbacks to soil moisture dynamics. Here, we introduce an integrated, process-based modelling framework, T&C-SMEW, which represents ecohydrological and ERW dynamics, along with microbially explicit biogeochemical processes. We compared framework simulations against a controlled mesocosm experiment and long-term field observations, demonstrating its ability to reproduce feedstock cation release, soil pH dynamics, gross primary production, and CO2 fluxes. T&C-SMEW reveals hydrological constraints and vegetation effects on ERW-mediated CDR by quantifying impacts on ecosystem respiration, net ecosystem exchange, and alkalinity export, emphasising the importance of ecohydrological modelling for ecosystem-level CDR estimation. These advances provide a modelling framework for identifying optimal deployment scenarios to establish ERW as a viable and operationally feasible CDR approach. 1 Introdu