Basaltic Rock Weathering as an Atmospheric CO2 Removal (CDR) Technique: A Review

Atmospheric CO2 concentrations have reached significant levels during the industrial era, necessitating the implementation of effective carbon dioxide removal (CDR) technologies. Enhanced Rock Weathering (ERW) using basalt has emerged as a high-potential strategy, leveraging its mafic composition to sequester CO2 as stable carbonates. This review analyzes ERW’s geochemical processes, application methods, and multifaceted co-benefits, such as restoring “background fertility” and improving soil structure. The literature indicates that while small-scale applications range from 1.5 to 6 Mg·ha−1·yr−1, intensive agricultural rates typically reach 40–100 Mg·ha−1·yr−1. Global models estimate a sequestration potential of up to 4.9 × 109 Mg CO2·yr−1 for basalt, although field-scale results vary significantly, reaching uptake rates of up to 4 Mg CO2·ha−1 depending on pedological conditions and crop types. Despite this promise, transitioning to large-scale deployment faces critical hurdles, including operational difficulties in mechanized spreading and a scarcity of audited, long-term field data. Future research must prioritize standardized protocols and comprehensive economic analyses to bridge the gap between theoretical models and empirical evidence. Ultimately, ERW represents a multifaceted solution for climate stabilization and sustainable food security, provided that sequestration efficacy and environmental safety are rigorously verified through high-application field trials.