The Potential Influence of Maritime Continent Deforestation on El Niño‐Southern Oscillation: Insights From Idealized Modeling Experiments

Abstract

During the past two decades, the Maritime Continent (MC) has experienced increased deforestation. Here we show, with ensemble idealized deforestation experiments, that the MC deforestation could potentially alter the complexity (i.e., event‐to‐event differences) of the El Niño‐Southern Oscillation (ENSO) in terms of its spatial pattern and temporal evolution. The deforestation model run increases the occurrences of the Central Pacific and multi‐year types of ENSO compared to the control experiments. This change in ENSO complexity can be attributed to MC's intensification of the subtropical ENSO dynamics, commonly known as the seasonal footprinting mechanism. The deforestation amplifies the mean state of the subtropical high over the northeastern Pacific, leading to an increased dominance of subtropical ENSO dynamics in determining the ENSO pattern and evolution. This idealized coupled climate modeling study suggests that MC deforestation has a potential to alter ENSO's complexity, making El Niño more complex and less predictable.

El Niño‐La Niña Asymmetries in the Changes of ENSO Complexities and Dynamics Since 1990

“…Also, the specific reasons for ENSO complexities and dynamics changes around 1990 remained debated. Previous studies linked causes to factors such as the Atlantic Meridional Oscillation (Lyu et al, 2017;Yu et al, 2015), North Atlantic Oscillation (Ding et al, 2023), global warming (Ashok et al, 2007;Yeh et al, 2009), or even deforestation in the Maritime Continent (Lee et al, 2023). However, further studies are required for comprehensive understanding of the underlying causes.…”