The Amazon rainforest has evolved over millions of years and even through ice ages. Yet today, human influences and global climate change put this huge ecosystem at risk of large-scale dieback—with major consequences for its capability as a global CO2 sink. New research published in Nature Geoscience now reveals a key player in shaping the resilience of the Amazon, and finds that regions with generally higher rainfall variability are more resilient to current and future climate disturbances. However, despite this “training effect,” the Amazon rainforest might not be able to keep up with the pace of ongoing climate change, the study shows.