Is El Niño really changing?

Abstract

AbstractEl Niño–Southern Oscillation (ENSO) is the leading mode of tropical Pacific climate variability, with global impacts. Understanding how the statistics of ENSO events may be changing in response to global warming is of great interest and importance for society. A clear detection of such signals in observations has, however, been obscured by large event‐to‐event differences and apparent “regime shifts” such as that of the late 1970s. In particular, despite extensive research, it is not clear to what extent the observed long‐term changes are systemic or random. Here we show using a multicomponent linear inverse modeling technique that statistically significant systemic changes have indeed occurred in ENSO dynamics since the late 1970s and have affected the evolution of El Niño and La Niña events from their embryonic to fully mature stages.