Moderate greenhouse climate and rapid carbonate formation after Marinoan snowball Earth

The Marinoan snowball Earth deglaciation led to a rapid warming, commonly hypothesized to be followed by a slow decline in the supergreenhouse climate through continental weathering. This study, using the ICON-ESM Earth system model, quantifies the ocean's role in atmospheric CO2 evolution after deglaciation. The model shows that the ocean's carbon cycle drives the supergreenhouse climate evolution through various mechanisms, resulting in scenarios ranging from rapid decline to intensification. Rapid carbonate formation from pre-existing ocean alkalinity is proposed as an explanation for Marinoan cap dolostones. The findings suggest a moderate and relatively short-lived supergreenhouse climate as a plausible scenario consistent with geological data, challenging the established hypothesis of a prolonged supergreenhouse.

Lennart Ramme, Tatiana Ilyina, Jochem Marotzke