Six-fold increase of atmospheric pCO ₂ during the Permian–Triassic mass extinction

Abstract

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 pCO ₂ and caused global warming. However, the magnitude of pCO ₂ changes during the PTME has not yet been estimated. Here, we present a continuous pCO ₂ record across the PTME reconstructed from high-resolution δ ¹³C of C ₃ plants from southwestern China. We show that pCO ₂ 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 pCO ₂ significantly correlates with sea surface temperatures. Mass balance modelling suggests that volcanic CO ₂ 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.

Abstract

The Permian–Triassic mass extinction was accompanied by a massive release of carbon into the ocean-atmosphere system, but the magnitude of change is not well known. Here, the authors present a new record of C ₃ plants from southwestern China which shows that atmospheric pCO ₂ increased by a factor of six during this event.