Six-fold increase of atmospheric pCO₂ during the Permian-Triassic mass extinction

The Permian-Triassic mass extinction was marked by a massive release of carbon into the ocean-atmosphere system, evidenced by a sharp negative carbon isotope excursion. Large carbon emissions would have increased atmospheric pCO₂ and caused global warming. However, the magnitude of pCO₂ changes during the PTME has not yet been estimated. Here, we present a continuous pCO₂ record across the PTME reconstructed from high-resolution δ¹³C of C₃ plants from southwestern China. We show that pCO₂ increased from 426 +133/-96 ppmv in the latest Permian to 2507 +4764/-1193 ppmv at the PTME within about 75 kyr, and that the reconstructed pCO₂ significantly correlates with sea surface temperatures. Mass balance modelling suggests that volcanic CO₂ is probably not the only trigger of the carbon cycle perturbation, and that large quantities of ¹³C-depleted carbon emission from organic matter and methane were likely required during complex interactions with the Siberian Traps volcanism.