Impacts of Forest Loss on the Global Water Cycle of the Permian-Triassic Extinction

Abstract

Recent studies have shown profound effects of deforestation on decreased precipitation and evapotranspiration. This can be attributed to the concept of green water, which is the volume of water stored in soils and interacting with plants via evapotranspiration. The Permian-Triassic (P-T) extinction had the most profound impact on plant life of any mass extinction, with many large forests being replaced by herbaceous lycophytes. The aim of this study is to explore a large-scale extreme example of deforestation by analyzing the green water variables of the Permian-Triassic extinction linked to the global loss of Glossopteris and related forests. When exploring this event, two main questions are focused on; how did the global distribution of green water differ after the extinction, and how could these alterations have affected global climate at the time? To answer these questions, variables from various studies are transferred into ArcPro and used to make first estimates of seasonal evapotranspiration, latent heat flux, and mean residence time before and after the P-T extinction. Results show a decrease in all water balance variables after the P-T and a correlation between areas of higher decrease and pre-extinction forests. When evapotranspiration change is converted to a change in sensible heat, a global change of approximately 2oC is observed, accounting for approximately one fifth of the post-extinction temperature increase. Keywords: Water Balance, Permian-Triassic Extinction, Evapotranspiration, Deforestation, Sensible Heat