Direct effects of CO 2 and temperature on silicate weathering: Possible implications for climate control
A critical uncertainty in models of the global carbon cycle and climate is the combined effect of organic activity, temperature, and atmospheric CO 2 on silicate weathering. Here we present new dissolution rates of anorthite and augite which indicate that silicate weathering in organic-rich solutions is not directly affected by soil CO 2 but is very sensitive to temperature. Apparently CO 2 accelerates silicate weathering indirectly by fertilizing organic activity and the production of corrosive organic acids. The weathering dependencies highlight the ability of silicate weathering to act as a global thermostat and damp out climate change, when used as input in steady-state carbon cycle and climate models.