A 60-million-year reconstruction links changing shelf area to phosphate availability, ocean oxygen and organic carbon burial, with the strongest feedback appearing at an intermediate sea level.
For roughly 60 million years, rising and falling seas appear to have helped regulate Earth’s climate through an overlooked feedback: sea level controlled how much phosphate remained available to ocean life, which altered how much carbon was buried on the seafloor and how much CO₂ stayed in the atmosphere — effectively acting as a planetary thermostat.
The Long View