Alkalinity responses to climate warming destabilise the Earth's thermostat

Alkalinity generation from rock weathering influences Earth's climate over geological timescales. While lithology is considered the primary control, the roles of other factors, especially differentiating climatic and erosional effects, remain unclear. This study uses global observations to demonstrate erosion rate's significance in regulating riverine alkalinity, alongside carbonate proportion, mean annual temperature (MAT), catchment area, and soil regolith thickness. Climate warming is projected to substantially alter ocean CO2 sequestration by 2100, potentially increasing or decreasing terrestrial alkalinity flux depending on emissions scenarios. A low-emissions scenario might reduce mid-latitude flux, while a high-emissions scenario could increase it.

Nele Lehmann, Tobias Stacke, Sebastian Lehmann, Hugues Lantuit, John Gosse, Chantal Mears, Jens Hartmann, Helmuth Thomas