Advancing Enhanced Weathering Modeling in Soils: Systematic Comparison
and Validation with Experimental Data
Abstract
Enhanced weathering (EW) is a promising strategy to remove atmospheric
CO2 by amending agricultural and forestry soils with ground silicate
materials. However, the current model-based assessments of EW potential
face uncertainties stemming from the intricate interplay among soil
physical, chemical, and biotic processes, compounded by the absence of a
detailed model-data comparison, mostly due to the limited availability
of comprehensive data. Here, we address this critical gap by advancing
and validating an ecohydrological and biogeochemical model for EW
dynamics in soils. We conduct a hierarchical validation in which model
results are critically compared to four experimental datasets of
increasing complexity, from simple closed incubation systems to open
mesocosm experiments. The comparison demonstrates the model ability to
capture the dynamics of primary variables, including rock alkalinity
release and CO2 sequestration. The comparison also reveals that
weathering rates are consistently lower than traditionally assumed by up
to two orders of magnitude. We finally discuss avenues for further
theoretical and experimental explorations.