Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?

Abstract Observed El Niño‐Southern Oscillation (ENSO) varies between decades with high ENSO amplitude and more extreme Eastern Pacific (EP) El Niño events and decades with low ENSO amplitude and mainly weak El Niño events. Based on experiments with the CESM1 model, ENSO may lock‐in into an extreme E...

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Main Authors: Tobias Bayr, Joke F. Lübbecke, Stephanie Fiedler
Format: Article
Language:English
Published: Wiley 2024-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2023GL107848
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author Tobias Bayr
Joke F. Lübbecke
Stephanie Fiedler
author_facet Tobias Bayr
Joke F. Lübbecke
Stephanie Fiedler
author_sort Tobias Bayr
collection DOAJ
description Abstract Observed El Niño‐Southern Oscillation (ENSO) varies between decades with high ENSO amplitude and more extreme Eastern Pacific (EP) El Niño events and decades with low ENSO amplitude and mainly weak El Niño events. Based on experiments with the CESM1 model, ENSO may lock‐in into an extreme EP El Niño‐dominated state in a +3.7 K warmer climate, while in a −4.0 K cooler climate ENSO may lock‐in into a weak El Niño‐dominated state. The state shift of ENSO with global warming can be explained by the location and amplitude of the strongest warming over the eastern equatorial Pacific, which amplifies the Bjerknes feedback and allows a southward migration of the Intertropical Convergence Zone onto the equator, a prerequisite of extreme EP El Niños. In light of these results, we discuss to what extent the state of ENSO may be a tipping element in the climate system.
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spelling doaj-art-1eb80ddeea164c32abf23d54cffb04522025-08-20T03:12:51ZengWileyGeophysical Research Letters0094-82761944-80072024-07-015113n/an/a10.1029/2023GL107848Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?Tobias Bayr0Joke F. Lübbecke1Stephanie Fiedler2Institute of Geophysics and Meteorology University of Cologne Cologne GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyInstitute of Geophysics and Meteorology University of Cologne Cologne GermanyAbstract Observed El Niño‐Southern Oscillation (ENSO) varies between decades with high ENSO amplitude and more extreme Eastern Pacific (EP) El Niño events and decades with low ENSO amplitude and mainly weak El Niño events. Based on experiments with the CESM1 model, ENSO may lock‐in into an extreme EP El Niño‐dominated state in a +3.7 K warmer climate, while in a −4.0 K cooler climate ENSO may lock‐in into a weak El Niño‐dominated state. The state shift of ENSO with global warming can be explained by the location and amplitude of the strongest warming over the eastern equatorial Pacific, which amplifies the Bjerknes feedback and allows a southward migration of the Intertropical Convergence Zone onto the equator, a prerequisite of extreme EP El Niños. In light of these results, we discuss to what extent the state of ENSO may be a tipping element in the climate system.https://doi.org/10.1029/2023GL107848ENSOEl Nino‐Southern Oscillationtipping elementglobal warmingextreme eastern Pacific El Nino events
spellingShingle Tobias Bayr
Joke F. Lübbecke
Stephanie Fiedler
Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?
Geophysical Research Letters
ENSO
El Nino‐Southern Oscillation
tipping element
global warming
extreme eastern Pacific El Nino events
title Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?
title_full Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?
title_fullStr Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?
title_full_unstemmed Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?
title_short Is El Niño‐Southern Oscillation a Tipping Element in the Climate System?
title_sort is el nino southern oscillation a tipping element in the climate system
topic ENSO
El Nino‐Southern Oscillation
tipping element
global warming
extreme eastern Pacific El Nino events
url https://doi.org/10.1029/2023GL107848
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