Mid‐late Holocene El Niño variability in the equatorial Pacific from coral microatolls

Oxygen isotope ratios in Porites microatolls from Christmas Island in the central Pacific provide high‐resolution proxy records of El Niño‐Southern Oscillation (ENSO) variability since 3.8 thousand years ago (ka). Compared with modern microatolls, reconstructions from fossil microatolls imply that interannual variations in ENSO sea‐surface temperature and precipitation were less intense 3.8–2.8 ka, but more pronounced at 1.7 ka. Amplification of ENSO at ∼2 ka is consistent with precessional changes in insolation seasonality, but exceeds model predictions and may reflect stronger rainfall teleconnections through enhanced interaction between the Southern Oscillation and the Pacific Intertropical Convergence Zone.