Researchers led by Bob Hilton showed that when volcanic CO₂ warmed early Earth, the oxidation of organic‑rich rocks released additional carbon, amplifying the temperature rise beyond what volcanic gases alone would cause. Co‑author Rugenstein questioned the size of that carbon flux, calling the estimates “enormous.”

The finding doesn’t overturn the classic “climate thermostat” model that relies on silicate weathering to draw down CO₂. Instead, it suggests silicate reactions must work harder to offset the extra greenhouse gas from organic carbon weathering. The feedback’s strength hinges on how much carbon‑laden sediment is exposed; once that source is exhausted, the effect wanes, while silicate minerals remain abundant.

The study implies similar feedbacks could surface during modern warming, adding CO₂ over the coming centuries. Hilton warns this extra release would shave a noticeable chunk off the remaining carbon budget, tightening the margin for human emissions. In practice, the process will modestly magnify anthropogenic warming but is not a runaway threat.