Zelinka et al. (2026) Recent cloud trends and extremes reaffirm established bounds on cloud feedback and aerosol-cloud interactions

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-03-31
• Authors: Mark D. Zelinka, Timothy A. Myers, Yi Qin, Li‐Wei Chao, Stephen A. Klein, Stephen Po-Chedley, Po-Lun Ma, Casey J. Wall, Paulo Ceppi, Andrew Gettelman
• DOI: 10.1038/s43247-026-03461-8

Research Groups

• Lawrence Livermore National Laboratory, Livermore, CA, USA
• Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
• Physical Science Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
• Pacific Northwest National Laboratory, Richland, WA, USA
• Laoshan Laboratory, Qingdao, China
• Department of Meteorology, Stockholm University, Stockholm, Sweden
• Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
• Department of Physics, Imperial College London, London, UK

Short Summary

This study quantifies the meteorological and aerosol-related factors driving recent cloud-radiative anomalies and increased Earth's energy imbalance, reaffirming established bounds on cloud feedback and aerosol forcing, and supporting an equilibrium climate sensitivity near 3 °C.

Objective

• To quantify the meteorological factors responsible for interannual cloud-radiative anomalies, including the extreme value observed in 2023, and their superposition on a background of declining sulfate aerosol concentrations.
• To assess the implications of these cloud changes for future Earth system evolution, specifically constraining cloud feedback and aerosol forcing, and to provide observational support for the equilibrium climate sensitivity.

Study Configuration

• Spatial Scale: Global, with a specific focus on Northern Hemisphere oceans where reduced cloud reflection is pronounced.
• Temporal Scale: The past two decades (since 2000), with detailed analysis of interannual variations and the extreme event in 2023.

Methodology and Data

• Models used: CMIP5 and CMIP6 climate models, WCRP ECS code, and cloud radiative kernels for feedback diagnosis.
• Data sources:
  • MODIS-COSP (Moderate Resolution Imaging Spectroradiometer - CloudSat/CALIPSO)
  • CERES-FBCT (Clouds and the Earth's Radiant Energy System - FluxByCldTyp)
  • ERA5 reanalysis (ECMWF Reanalysis v5)
  • EAC4/CAMS reanalysis (Copernicus Atmosphere Monitoring Service global reanalysis)
  • MODIS-derived Nd (cloud droplet number concentration)

Main Results

• Earth’s energy imbalance has significantly increased over the past two decades, reaching a record in 2023, primarily due to reduced reflection of sunlight by low-level clouds, particularly over Northern Hemisphere oceans.
• Interannual cloud-radiative anomalies are attributed to specific meteorological variations, which collectively led to the extreme 2023 value.
• A sustained decrease in cloud reflection over the past 22 years is also linked to a background reduction in sulfate aerosol concentrations.
• The derived constraints on cloud feedback and aerosol forcing are consistent with prior research, indicating no emerging stronger cloud feedback or underestimated future warming.
• The findings support an equilibrium climate sensitivity of approximately 3 °C, with a likely range of 2.7–4.1 °C.

Contributions

• Provides a quantitative, observationally-driven analysis of the combined meteorological and aerosol drivers of recent cloud trends and extreme cloud-radiative anomalies.
• Reaffirms the established range of cloud feedback and aerosol-cloud interactions, mitigating concerns about a potentially stronger-than-expected cloud feedback.
• Offers updated observational constraints that reinforce the current understanding of equilibrium climate sensitivity, contributing to reduced uncertainty in climate projections.

Funding

• U.S. Department of Energy (DOE) Office of Science Biological and Environmental Research program, Regional and Global Model Analysis program area (Contract DE-AC52-07NA27344).
• NOAA cooperative agreement NA22OAR4320151.
• Enabling Aerosol-cloud interactions at GLobal convection-permitting scalES (EAGLES) project (project no. 74358), funded by the U.S. DOE, Office of Science, Office of Biological and Environmental Research, Earth System Model Development (ESMD) and Regional & Global Model Analysis (RGMA) program areas.
• European Union (ERC, AC3S, project number 101156240).
• UK Research and Innovation (UKRI) under the UK government’s Horizon Europe funding Guarantee (grant EP/Y036123/1).
• UK Natural Environmental Research Council (NERC) grants NE/V012045/1 and NE/T006250/1.
• National Energy Research Scientific Computing Center (NERSC) (NERSC award BER-ERCAP0033047).
• World Climate Research Programme (WCRP) Working Group on Coupled Modelling (CMIP).

Citation

@article{Zelinka2026Recent,
  author = {Zelinka, Mark D. and Myers, Timothy A. and Qin, Yi and Chao, Li‐Wei and Klein, Stephen A. and Po-Chedley, Stephen and Ma, Po-Lun and Wall, Casey J. and Ceppi, Paulo and Gettelman, Andrew},
  title = {Recent cloud trends and extremes reaffirm established bounds on cloud feedback and aerosol-cloud interactions},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03461-8},
  url = {https://doi.org/10.1038/s43247-026-03461-8}
}