High rainfall afforded resilience to tropical rainforests during Early Eocene Climatic Optimum

The rainforests near the early Eocene palaeo-equator were more resilient to greenhouse warming than mid-latitude vegetation. The mechanism underlying that resilience remains poorly known due to the lack of reliable terrestrial climate data from the palaeo-equator. In this paper, we quantify terrestrial temperature data using a plant proxy approach and infer that early Eocene climate near the palaeo-equator (∼2.6° N) was warmer than in mid- to high palaeolatitudes. The data also suggest that high levels of rainfall near the palaeo-equator might have afforded greater resilience to tropical rainforests by increasing the water use efficiency of trees during the warm greenhouse world of the Early Eocene Climatic Optimum.