Science – Bufe et al. (2024): CO2 drawdown from weathering is maximized at moderate erosion rates

Aaron Bufe, Jeremy K. C. Rugenstein, Niels Hovius IN: Science, DOI: 10.1126/science.adk0957

 Solute-chemistry datasets from mountain streams in different orogens isolate the impact of erosion on silicate weathering—a carbon dioxide (CO₂) sink—and coupled sulfide and carbonate weathering—a CO₂ source. Contrasting erosion sensitivities of these reactions produce a CO₂-drawdown maximum at erosion rates of ~0.07 millimeters per year. Thus, landscapes with moderate uplift rates bolster Earth’s inorganic CO₂ sink, whereas more rapid uplift decreases or even reverses CO₂ sequestration. This concept of an “erosion optimum” for CO₂ drawdown reconciles conflicting views on the impact of mountain building on the carbon cycle and permits estimates of geologic CO₂ fluxes dependent upon tectonic changes.

LINK