Fahrenbach et al. (2026) Amplification of ENSO-driven vegetation variability at decadal and longer timescales

Identification

• Journal: Earth System Dynamics
• Year: 2026
• Date: 2026-07-13
• Authors: Nora L. S. Fahrenbach, Robert C. J. Wills
• DOI: 10.5194/esd-17-987-2026

Research Groups

• Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland (Nora L. S. Fahrenbach and Robert C. J. Wills)

Short Summary

This study investigates the decadal and multi-decadal influence of ENSO, PDO, and AMV on global vegetation variability using long-term pre-industrial control simulations from multiple CMIP6 Earth System Models (ESMs) with interactive LAI.

Objective

• Investigate the low-frequency amplification of ENSO-driven vegetation variability globally and regionally.
• Examine the impact of the PDO and AMV on LAI variability on decadal and multi-decadal timescales.
• Determine the dominant physical process through which ENSO-induced memory in LAI is established.
• Assess whether LAI memory manifests in ecosystem carbon fluxes (GPP and NPP).

Study Configuration

• Spatial Scale: Global, with a focus on tropical hotspots such as the northern Amazon and Southeast Asia.
• Temporal Scale: Decadal to multi-decadal timescales.

Methodology and Data

• Models used: 11 CMIP6 ESMs with interactive LAI (ACCESS-ESM1-5, CanESM5, CMCC-ESM2, CESM2, EC-Earth3-Veg, GFDL-ESM4, IPSL-CM6A-LR, MIROC-ES2L, MPI-ESM1-2-LR, NorESM2-LM, and UKESM1-0-LL).
• Data sources: CMIP6 pre-industrial control simulations, historical CMIP6 simulations, and satellite-based observations (GLASS mission).

Main Results

• A spectral reddening of ENSO-driven vegetation variability is found, with a 20%–25% amplification of the LAI signal at multi-decadal timescales and a 25%–65% reduction at interannual timescales.
• The coherence between ENSO and LAI at these multi-decadal timescales is largely governed by a direct pathway (88%), while the PDO only acts as a weak mediator (12%).

Contributions

• This study provides new insights into the frequency-dependent coupling between the land surface and atmosphere-ocean variability, which can be leveraged as a source of predictability in decadal climate predictions.
• The results highlight the importance of considering the terrestrial memory of multi-decadal climate signals in understanding long-term variability in vegetation and the terrestrial carbon cycle.

Funding

• This research was funded by the Swiss National Science Foundation (SNSF) under grant number [insert grant number].

Citation

@article{Fahrenbach2026Amplification,
  author = {Fahrenbach, Nora L. S. and Wills, Robert C. J.},
  title = {Amplification of ENSO-driven vegetation variability at decadal and longer timescales},
  journal = {Earth System Dynamics},
  year = {2026},
  doi = {10.5194/esd-17-987-2026},
  url = {https://doi.org/10.5194/esd-17-987-2026}
}