In a recent paper published in Scientific Reports led by Yancheng Zhang (University of Bremen, Germany), the authors suggest a new possible mechanism explaining how the slowdown of the Atlantic Meridional Overturning Circulation regulated the spatial characteristics of precipitation changes across tropical South America during Heinrich Stadial 1. This indicates that the Atlantic forcing (e.g., interhemispheric sea surface temperature gradient) was not as significant as previously thought. The authors (among them Prof. Dr. Cristiano M. Chiessi, from the P2L) compiled 107 published hydrological paleorecords over South America and operated a set of sensitivity climate model experiments to evaluate the contribution of the Atlantic and eastern Pacific sea surface temperature anomalies on Amazonian Andes precipitation during Heinrich Stadial 1. By doing this, they were able to show that an eastern equatorial Pacific sea surface temperature increase (i.e., 0.5–1.5 °C) is crucial to generate wet conditions in the Amazonian Andes. The mechanism works via anomalous low sea level pressure over the eastern equatorial Pacific, which promotes a regional easterly low-level wind anomaly and moisture recycling from central Amazonia towards the Andes. To read the full paper, please click here.