Sensitivity of climate and atmospheric CO2 to deep-ocean and shallow-ocean carbonate burial

Previous models of physical and biogeochemical controls of the evolution of atmospheric CO₂ and climate over hundreds of millions of years have neglected the effect of variations in the balance between shallow-ocean and deep-ocean carbonate deposition. This is important because the relative proportions of carbonate burial in the two reservoirs have changed over time. Here I set up a model of the carbonate-silicate geochemical cycle that distinguishes carbonate masses produced by the two types of burial and shows that reasonable increases in deep-ocean burial could produce substantial warmings over a few hundred million years. The model includes exchanges between crust and mantle; transients from burial shifts are found to be sensitive to the fraction of non-degassed carbonates subducted into the mantle. Without the habitation of the open ocean by plankton such as foraminifera and coccolithophores, today's climate would be substantially colder. -Author