Arielle Woods, Don Rodbell, Mark Abbott, Robert George Hatfield, Christine Y Chen , Sophie Lehmann, David McGee, Nick Weidhaas, Pedro Tapia, Blas Lorenzo Valero-Garcés

A sediment core spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes reveals abrupt climatic events on a centennial-millennial time scale. These events, which involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake, occurred during the abrupt warmings recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials. Lake Junín is the first record to document the response of Andean glaciers to serial DO events, and also reveals the magnitude of the hydroclimatic disruptions in the highest reaches of the Amazon Basin that were caused by a weakening of the South American summer monsoon during abrupt arctic warming. Ongoing warming in the Arctic could lead to significant reductions in the precipitation-evaporation balance in the tropical Andes with deleterious effects on the sustainability of a densely populated region of South America.