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.