Early Triassic super-greenhouse climate driven by vegetation collapse

Abstract The Permian–Triassic Mass Extinction (PTME), life’s most severe crisis1, has been attributed to intense global warming triggered by CO2 emissions from Large Igneous Province volcanism2–8. It remains unclear, however, why super-greenhouse conditions persisted for around five million years after the volcanic episode, when Earth system feedbacks should have returned temperatures to pre-extinction levels within a few hundred thousand years8. Here we use fossil occurrences and lithological indicators of climate to reconstruct spatio-temporal maps of plant productivity and biomass changes through the Permian–Triassic and undertake climate-biogeochemical modelling to investigate the unusual longevity and intensity of warming. Our reconstructions show that terrestrial vegetation collapse during the PTME, especially in tropical regions, resulted in an Earth system with low levels of organic carbon sequestration and chemical weathering, leading to limited drawdown of greenhouse gases. This led to a protracted period of extremely high surface temperatures, during which biotic recovery was delayed for millions of years. Our results support the idea that thresholds exist in the climate-carbon system beyond which warming may be amplified substantially.