Climate network and complexity based ENSO forecast for 2026

Abstract

The El Ni\~no Southern Oscillation (ENSO) is the dominant driver of interannual global climate variability and can lead to extreme weather events such as droughts or flooding. Recently, we have developed several statistical approaches for early ENSO forecasting, in particular, its El Ni\~no phase. The climate network-based approach allows forecasting the onset of an El Ni\~no event or its absence about 1 year ahead [1]. The complexity-based approach allows additionally to forecast the magnitude of an upcoming El Ni\~no event in the calendar year before the onset [2]. Additionally, we have developed methods for forecasting the type (Eastern Pacific or Central Pacific) of an El Ni\~no [3] and for probabilistic forecasting of La Ni\~na and neutral events [4], also by the end of the calendar year before the event. Here we present the forecasts of these methods for 2026. The climate network and the complexity-based approach do not provide concurring signals for this year. The combined forecast indicates that a neutral event is more likely than an El Ni\~no. If an El Ni\~no develops in 2026, the complexity-based approach predicts a weaker event with a magnitude of $0.84\pm0.36${\deg}C.