Abrupt mid‐Holocene onset of centennial‐scale climate variability on the Peru‐Chile Margin

Understanding the natural climate variations in the eastern tropical Pacific (ETP) is crucial for predicting the evolution of the El Niño‐Southern Oscillation (ENSO). Here we present the first continuous, decadal‐resolution Holocene climate record from the Peru‐Chile Margin, near the epicenter of the modern ENSO system. Geochemical proxies allow us to reconstruct sea surface temperature, phytoplankton productivity, and thermocline ventilation, variables that are tightly correlated to ENSO events today. Despite the observation that the mean state of all three variables did not change over the past 10,000 years, our data reveal a dramatic increase in climate variability near 5 ka; represented by prolonged periods (50–200 yrs) of climate extremes, which are absent in the early Holocene. These centennial‐scale oscillations do not show typical El Niño‐La Niña correlations between proxies. We therefore posit that a significant fraction of super‐ENSO variance may originate outside the tropics, through processes that ventilate the ETP subsurface waters.