The effects of CO2 increase and its link to the mass extincton at the Permo-Triassic boundary

The Permo–Triassic Boundary (PTB) marks a time of profound climatic change. Near the PTB (~252 Ma), the largest known mass extinction occurred with more than 90% of marine species and 70% of terrestrial species became extinct. The mass extinction is linked to a massive warming event at the PTB, where tropical regions became too hot for survival ofspecies. The increase in atmospheric CO₂ during the Permian and the PTB is mainly attributed to the decrease of chemically weatherable fresh silicate rock due to orogenesis, and the CO₂ released in the atmosphere from the Siberian Traps. In this study, we use the UK Met Office fully coupled HadCM3L General Circulation Model (GCM) to perform Permo-Triassic climate simulations with different atmospheric CO₂ values that encompass most of the estimates of atmospheric CO₂ concentration during this time, to provide more insights about the climate changes during the end Permian – early Triassic. Specifically, we focus on: a) the spatial extension of dry conditions/lethally hot temperatures under different CO₂ conditions, b) the seasonal surface temperature difference and precipitation changes at higher latitudes and c) the effects of increased atmospheric CO₂ on the large-scale wind and monsoonal circulation.