Coquereau et al. (2025) Increase in ENSO Frequency and Intensity Under 20th and 21st Century Warming: Insights From CMIP6 Large Ensembles

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-11-11
• Authors: Arthur Coquereau, Florian Sévellec, Thierry Huck, Alexey V. Fedorov
• DOI: 10.1029/2025gl116541

Research Groups

Not specified in the provided abstract. The study utilizes CMIP6 climate models, implying a collaborative effort from various international modeling centers.

Short Summary

This study analyzes CMIP6 large-ensemble simulations to demonstrate that anthropogenic warming increases El Niño-Southern Oscillation (ENSO) frequency and strengthens its intensity, primarily driven by a shift towards Eastern Pacific El Niño and an overall increase in both EP and CP variability.

Objective

• To assess the response of El Niño-Southern Oscillation (ENSO) to external anthropogenic forcing using state-of-the-art CMIP6 large-ensemble simulations.

Study Configuration

• Spatial Scale: Global, with a specific focus on the Eastern Pacific (EP) and Central Pacific (CP) regions relevant to ENSO variability.
• Temporal Scale: Centennial scale, projecting future changes in ENSO under anthropogenic warming and examining past observed intensification.

Methodology and Data

• Models used: State-of-the-art large-ensemble simulations from CMIP6 climate models.
• Data sources: Large-ensemble simulations generated by CMIP6 climate models.

Main Results

• In most CMIP6 models, ENSO frequency increases under anthropogenic warming.
• This increase in ENSO frequency is driven by two factors: a shift towards the Eastern Pacific (EP) El Niño pattern (characterized by higher frequencies and greater amplitudes), and an overall increase in the frequency of both EP and Central Pacific (CP) variability.
• These changes in ENSO frequency and pattern scale with the intensity of anthropogenic forcing.
• Most models also project ENSO strengthening that commences and continues throughout the 21st century.
• The observed intensification of ENSO during the second half of the 20th century could be of anthropogenic origin.

Contributions

• Provides robust evidence, utilizing state-of-the-art CMIP6 large-ensemble simulations, that anthropogenic warming leads to increased ENSO frequency and intensity.
• Identifies the key mechanisms driving the increased ENSO frequency: a shift towards the Eastern Pacific El Niño pattern and an overall increase in both EP and CP variability.
• Suggests a potential anthropogenic attribution for the observed ENSO intensification during the latter half of the 20th century.

Funding

Not specified in the provided abstract.

Citation

@article{Coquereau2025Increase,
  author = {Coquereau, Arthur and Sévellec, Florian and Huck, Thierry and Fedorov, Alexey V.},
  title = {Increase in ENSO Frequency and Intensity Under 20th and 21st Century Warming: Insights From CMIP6 Large Ensembles},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl116541},
  url = {https://doi.org/10.1029/2025gl116541}
}