Sulfide weathering: carbon cycle fool’s gold

Sulfide weathering releases sulfuric acid eventually leading to a source of atmospheric CO2. This process has been widely discussed for its carbon source effect, notably in regard to Cenozoic climate evolution. Less attention has been drawn –in those discussion– to its interconnection with oxygen and sulfur cycles.
Because a perturbation (for instance, an increase) of sulfide weathering affects the C, O and S cycles, it triggers a cascade of geochemical feedbacks. The overall response of the Earth system to this perturbation therefore depends on the strength and timing of those feedbacks, and may not be straightforward.
Here we used the geochemical cycle model GEOCLIM to explore the sensitivity of transient climate evolution to an increase of sulfide weathering on million-year timescales, taking into account the perturbations and feedbacks of those 3 cycles.