Forests, climate, and silicate rock weathering
Carbonate–silicate cycle models have helped us to gain a quantitative understanding of the potential impacts of a wide range of factors on the long-term global carbon cycle. Here we investigate how to represent these factors in carbonate-silicate cycle models.
Over time periods of 10^6 years and longer, atmospheric carbon dioxide content is largely controlled by a balance between silicate rock weathering and CO2 sources (degassing from the Earth plus net organic carbon oxidation). Vegetation cover can affect silicate rock weathering rates by increasing soil CO2 content, stabilizing soil cover, and producing organic acids. Forests absorb more solar radiation than most other ecosystems; this tends to warm Earth's climate, especially outside of the tropics; this warmth would tend to increase silicate rock weathering rates. Here, we develop preliminary parameterizations of this effect that could be incorporated into carbonate–silicate cycle models, based on the results of general circulation model simulations.