Diversity in the Persistence of El Niño Events Over the Last Millennium

Abstract

AbstractThe El Niño Southern Oscillation (ENSO) is a mode of internal climate variability with far‐reaching impacts. Here, we consider an important aspect of ENSO behavior: the diversity in the persistence of El Niño events. We examine the occurrence of multi‐year El Niño events in instrumental observations, a suite of global climate model simulations of the last millennium, and paleoclimate archives. We find evidence of multi‐year El Niño events in all data sources considered, with a wide range of variability in the frequency of such events across and within the individual sources. Although scarce over the relatively brief satellite era, multi‐year El Niño events are often associated with the warmest El Niño events in observations and most models. Furthermore, we show that multi‐year El Niño events augment the persistence of associated hydroclimate anomalies, which may compound the impacts on vulnerable economies and ecosystems within and beyond the tropical Pacific sector.