Numerous lines of geochemical and stable isotopic evidence indicate that the end-Permian mass extinction was accompanied by abrupt climate change induced by CO2 addition. Catastrophic end-Permian Siberian volcanism may have released a large amount of CO2 into the atmosphere and pushed the Earth’s system beyond a critical threshold, causing the mass extinction. However, the injection rate, total amount and source of CO2 are largely unknown. We conducted a suite of simulations using the recently published carbon isotope records and U-Pb ages from Meishan section in Zhejiang province, China. An Earth System Model of Intermediate Complexity (cGENIE; http://www.genie.ac.uk) was used to extract the pattern of CO2 release needed to replicate the observed carbon isotope excursion across the Permian-Triassic boundary. This analysis leads us to suggest that the source of CO2 must have been significantly heavier than typical biogenic or thermogenic methane to explain the significant warming that occurred during and after the extinction event. Nevertheless, as with the Paleocene-Eocene Thermal Maximum, end-Permian rates of CO2 addition were likely small compared with modern fossil-fuel burning, but considerably more protracted, such that the likely total CO2 emitted significantly exceeded the modern fossil-fuel reserves. Peak emission rates corresponded to the onset of the maximum extinction interval, consistent with carbon cycle disruption, including volcanogenic CO2-induced warming (and perhaps ocean acidification) as a trigger for the end-Permian mass extinction.
Cui Y., Kump L. R. & Ridgwell A., in press. Initial assessment on the carbon emission rate and climatic consequences during the end-Permian mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology. Article (subscription required).