An Ecosystem of Carbon Dioxide Removal Reviews – Part 3: Enhanced Weathering

Enhanced Weathering (EW) is an emerging Carbon Dioxide Removal (CDR) approach within a growing portfolio of mitigation strategies, offering the potential for durable CDR alongside agronomic co-benefits. As interest in CDR increases, EW is transitioning from a primarily scientific concept toward early-stage implementation, requiring a comprehensive synthesis of the current evidence base. This systematic review focuses primarily on soil-based EW using silicate rock feedstocks. Across empirical and modelling studies, area-normalized CDR fluxes have a median value of 0.84 tonnes of carbon dioxide per hectare per year (tCO2 ha⁻1 yr⁻1) and span several orders of magnitude. The variance in reported fluxes reflects not only context-dependent differences in EW performance, but also the diversity of quantification approaches, which differ by use case and vary in terms of their system boundaries and treatment of loss processes. When scaled globally, evidence from empirical constraints and/or modelling approaches converges on a maximum technical CDR potential of ~0.2–2 GtCO2 yr⁻¹, though some estimates are higher. Significant uncertainty remains regarding the magnitude, persistence, and timing of loss processes after initial CDR has occurred, including secondary phase formation and cation exchange, and in how these losses depend on local soil and climate conditions and deployment strategies. Interactions with soil organic carbon introduce additional uncertainty but also the potential for increasing total CDR. Beyond CDR, EW is consistently associated with improvements in soil properties and crop productivity. Its deployment within managed land systems creates opportunities for synergies with other land-based CDR approaches, enabling combined inorganic and biological carbon sequestration. At the same time, EW raises important socio-economic and governance considerations, including distributional impacts, environmental risks, and conditional public support. Overall, EW represents a context-dependent and multifunctional CDR pathway, with increasing evidence for its potential to contribute to both climate mitigation and multiple Sustainable Development Goals. Its effective and scalable deployment will depend on improved standardisation, robust monitoring and verification, and alignment with economic, environmental, and societal constraints.