Chemical Weathering, Atmospheric CO₂, and Climate

TLDR

Chemical weathering’s influence on atmospheric CO₂ and climate is debated, with laboratory evidence showing strong temperature dependence but field signals often masked by co‑varying environmental factors. Field data link erosion rates to runoff, underscoring hydrological control, while models and the geological record demonstrate that weathering has both stabilized long‑term climate and driven climate swings via tectonic and paleogeographic changes.

Abstract

There has been considerable controversy concerning the role of chemical weathering in the regulation of the atmospheric partial pressure of carbon dioxide, and thus the strength of the greenhouse effect and global climate. Arguments center on the sensitivity of chemical weathering to climatic factors, especially temperature. Laboratory studies reveal a strong dependence of mineral dissolution on temperature, but the expression of this dependence in the field is often obscured by other environmental factors that co-vary with temperature. In the field, the clearest correlation is between chemical erosion rates and runoff, indicating an important dependence on the intensity of the hydrological cycle. Numerical models and interpretation of the geologic record reveal that chemical weathering has played a substantial role in both maintaining climatic stability over the eons as well as driving climatic swings in response to tectonic and paleogeographic factors.