Yang et al. (2025) Aerosol emission reductions cause post-2011 rapid warming in the northwestern Pacific

Identification

• Journal: Communications Earth & Environment
• Year: 2025
• Date: 2025-11-25
• Authors: Nan Yang, Yan Xia, Fei Xie, Chuanfeng Zhao, Tianyi Fan, Yannian Zhu
• DOI: 10.1038/s43247-025-03015-4

Research Groups

• Faculty of Geographical Science/School of System Science, Beijing Normal University, Beijing, China
• Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
• Institute of Carbon Neutrality, Peking University, Beijing, China
• School of Atmospheric Sciences, Nanjing University, Nanjing, China
• Joint International Research Laboratory of Atmospheric and Earth System Sciences & Institute for Climate and Global Change Research, Nanjing University, Nanjing, China

Short Summary

This study identifies anthropogenic aerosol emission reductions as the primary driver of the anomalously rapid warming observed in the northwestern Pacific since 2011, attributing this warming to increased surface shortwave radiation resulting from decreased cloud cover. The research reveals a five-year lag in ocean warming, governed by a threshold-triggered nonlinear aerosol-cloud interaction.

Objective

• To identify and quantify the principal drivers of the anomalously rapid warming in the northwestern Pacific since 2011, which has caused significant climate disasters and marine ecosystem destruction.
• To isolate the impacts of anthropogenic aerosols, greenhouse gases, and natural forcing on this regional warming.

Study Configuration

• Spatial Scale: Northwestern Pacific region (15°N–45°N, 120°E–170°E).
• Temporal Scale: Primarily 2011–2022 for observational analysis, with some data extending from 1950 or 2000, and 2011–2020 for CMIP6 simulations.

Methodology and Data

• Models used:
  • Simplified thermodynamic relationship for heat budget analysis.
  • Coupled Model Intercomparison Project Phase 6 (CMIP6) single-forcing experiments: 'hist-AER' (anthropogenic aerosol-forced only), 'hist-GHG' (greenhouse gas-forced only), and 'hist-NAT' (natural-forced only).
• Data sources:
  • Aerosol Optical Depth (AOD): MODIS (MOD08_M3), MERRA-2 reanalysis.
  • Sea Surface Temperature (SST): ERA5 reanalysis, NOAA Extended Reconstructed SST V5 (ERSST), Hadley Centre SST data set (HadISST).
  • Radiation Components, Heat Fluxes, Cloud Parameters, Sea Level Pressure (SLP): ERA5 reanalysis, CERESEBAFEdition4.2.
  • Mixed Layer Depth (MLD): NCEP Global Ocean Data Assimilation System (GODAS).
  • Atmospheric Variables: NCEP-NCAR Reanalysis 1 (relative humidity (RH), lower-tropospheric stability (LTS)).
  • Climate Indices: NOAA Climate Prediction Center (Arctic Oscillation - AO), NOAA Physical Sciences Laboratory (Pacific Decadal Oscillation - PDO).

Main Results

• The northwestern Pacific experienced an anomalously rapid warming of approximately 0.76 ± 0.22 °C/decade (ERA5) during 2011–2022, exceeding seven-fold the global oceanic warming rate.
• This rapid warming is primarily driven by an increase in surface shortwave radiation (SW), which contributed 72 ± 28 % to the observed SST rise, with SW increasing by 6.1 ± 2.4 W m⁻²/decade.
• Anthropogenic aerosol mitigation is identified as the principal driver, with aerosol optical depth (AOD) significantly decreasing by –0.03 ± 0.01 /decade in MERRA-2 during 2011–2022.
• Aerosol reductions led to a significant decrease in low cloud cover by –2.3 ± 0.91 %/decade (ERA5), enhancing surface SW absorption.
• A five-year lag was observed between aerosol emission reductions and the onset of decreased cloud cover and ocean warming, governed by a threshold-triggered nonlinear aerosol-cloud interaction where cloud decrease occurs only when AOD falls below a critical threshold of 0.2.
• CMIP6 single-forcing simulations attribute 66 ± 51 % of the SST increase (0.25 ± 0.14 °C/decade) in the northwestern Pacific during 2011–2020 to anthropogenic aerosols.
• Greenhouse gases (GHGs) contributed 30.84 ± 31.33 % (0.12 ± 0.11 °C/decade), while natural forcing played a minor role (2.6 ± 2.5 %, 0.01 ± 0.09 °C/decade).

Contributions

• Provides robust evidence, through a synthesis of reanalysis datasets, satellite observations, and CMIP6 multi-model ensembles, that anthropogenic aerosol mitigation is the dominant driver of the rapid post-2011 warming in the northwestern Pacific.
• Quantifies the significant contribution of increased shortwave radiation, resulting from reduced cloud cover due to aerosol reductions, to the observed sea surface temperature rise.
• Discovers and explains a novel five-year temporal lag in ocean warming following aerosol mitigation, attributed to a threshold-controlled nonlinear aerosol-cloud interaction.
• Highlights the critical implications of this "climate whiplash" effect for future climate policy formulation, marine ecosystems, and associated climate disasters.

Funding

• National Key Research and Development Program of China, Grant number 2024YFF0809402.
• World Climate Research Programme (WCRP) through its Working Group on Coupled Modelling (CMIP6).
• Earth System Grid Federation (ESGF).
• Multiple funding agencies supporting CMIP6 and ESGF.

Citation

@article{Yang2025Aerosol,
  author = {Yang, Nan and Xia, Yan and Xie, Fei and Zhao, Chuanfeng and Fan, Tianyi and Zhu, Yannian},
  title = {Aerosol emission reductions cause post-2011 rapid warming in the northwestern Pacific},
  journal = {Communications Earth & Environment},
  year = {2025},
  doi = {10.1038/s43247-025-03015-4},
  url = {https://doi.org/10.1038/s43247-025-03015-4}
}