Screen et al. (2025) Causes and consequences of Arctic amplification elucidated by coordinated multimodel experiments

Identification

• Journal: Communications Earth & Environment
• Year: 2025
• Date: 2025-12-06
• Authors: James A. Screen, Alexandre Audette, Russell Blackport, Clara Deser, Mark England, Nicole Feldl, Melissa Gervais, Stephanie Hay, Paul J. Kushner, Yu-Chiao Liang, Rym Msadek, Regan Mudhar, Michael Sigmond, Doug Smith, Lantao Sun, Hao Yu
• DOI: 10.1038/s43247-025-03052-z

Research Groups

• Department of Mathematics and Statistics, University of Exeter, Exeter, UK
• Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, USA
• Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, Canada
• National Center for Atmospheric Research, Boulder, USA
• Department of Meteorology and Atmospheric Science, Penn State University, University Park, USA
• Department of Physics, University of Toronto, Toronto, Canada
• Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan
• CECI, CNRS, IRD, CERFACS, Université de Toulouse, Toulouse, France
• Met Office Hadley Centre, Met Office, Exeter, UK
• Department of Atmospheric Science, Colorado State University, Fort Collins, USA

Short Summary

This perspective synthesizes scientific advances facilitated by the Polar Amplification Model Intercomparison Project (PAMIP), elucidating the critical roles of sea-ice loss and associated feedbacks in Arctic amplification and identifying robust, albeit often weak, remote tropospheric responses that contribute to projected climate change.

Objective

• To synthesize recent advances in understanding the causes and consequences of polar amplification, particularly those facilitated by the Polar Amplification Model Intercomparison Project (PAMIP).

Study Configuration

• Spatial Scale: Global, with a focus on Arctic, Antarctic, and Northern Hemisphere mid-latitudes (e.g., North Atlantic, North Pacific, North America, Europe).
• Temporal Scale: Year-long simulations, covering preindustrial, present-day (1979-2008), and future climate states, with analysis across seasonal (warm/cold half-year, winter, summer), annual, interannual, and decadal timescales.

Methodology and Data

• Models used: Coordinated multimodel experiments from the Polar Amplification Model Intercomparison Project (PAMIP), including atmospheric-only models and coupled atmosphere-ocean-ice models. Experiments involved prescribed sea ice cover and/or sea surface temperatures (SSTs), and some utilized nudging or albedo reduction techniques. Very large ensembles (up to ~2000 members) were used in some studies.
• Data sources: PAMIP simulations data, freely available at the Earth System Grid Federation (ESGF). Observational constraints were used to narrow uncertainties in model projections.

Main Results

• Surface heat flux changes and feedbacks (lapse rate, Planck, cloud) triggered by sea-ice loss are critical to explain the magnitude and seasonality of Arctic amplification, maximizing in winter due to enhanced oceanic heat release.
• Robust tropospheric responses to Arctic sea-ice loss include local warming and moistening, equatorward shifts of the jet stream and storm track in the North Atlantic, and fewer and milder cold extremes over North America.
• While generally small compared to simulated internal variability, the response to Arctic sea-ice loss makes a non-negligible contribution to projected climate change, notably for North Atlantic jet trends and their uncertainty.
• Model diversity in simulated responses has provided pathways to observationally constrain the real-world response; for example, observed eddy feedback suggests models may underestimate the jet shift, while observed neck region winds suggest models match it.
• Arctic sea-ice loss is critical for amplified wetting in the Arctic, primarily through increased evaporation, while SST warming increases Arctic precipitation through increased moisture convergence.
• Ocean-atmosphere coupling modulates the response to sea-ice loss, with coupled models showing enhanced weakening of winter storm tracks and deeper Arctic warming compared to uncoupled experiments.
• Storylines based on different sea-ice sensitivities to global warming (e.g., 1.5 to 3.8 million km² per degree Celsius of global SST warming) show varying magnitudes of Arctic warming (2.7 K to 4.2 K), Arctic wetting (0.12 mm/day to 0.18 mm/day), and North Atlantic jet shifts.

Contributions

• Provided a comprehensive synthesis of recent scientific advances in understanding the causes and consequences of polar amplification, specifically those facilitated by the PAMIP.
• Identified robust large-scale tropospheric circulation responses to Arctic and Antarctic sea-ice loss across multiple models, effectively separating forced changes from internal variability.
• Elucidated the physical mechanisms driving these responses, such as the multi-step process leading to jet stream shifts.
• Highlighted the importance of model diversity in responses as a pathway to observationally constrain real-world climate projections.
• Clarified the distinct and often opposing roles of Arctic sea-ice loss and global sea surface temperature warming in shaping regional climate changes and extreme weather events.
• Outlined critical future research directions, including addressing hemispheric asymmetry, refining experimental protocols (e.g., ocean coupling, regional CO2 forcing), utilizing new models (e.g., high-resolution, AI-based), and fostering enhanced interdisciplinary collaboration.

Funding

• NERC ArctiCONNECT project (NE/V005855/1)
• National Center for Atmospheric Research (NCAR), sponsored by the National Science Foundation (Cooperative Agreement 1852977)
• Royal Commission for the Exhibition of 1851 research fellowship
• NSF Grant AGS-1753034
• NSF PHY-2309135 to the Kavli Institute for Theoretical Physics (KITP)
• National Science and Technology Council (113-2628-M-002-018 and 113-2116-M-008-024)
• NERC GW4+ Doctoral Training Partnership studentship (NE/S007504/1)
• Met Office Hadley Centre Climate Programme funded by DSIT
• NSF Grant AGS-2300038
• Chinese Scholarship Council

Citation

@article{Screen2025Causes,
  author = {Screen, James A. and Audette, Alexandre and Blackport, Russell and Deser, Clara and England, Mark and Feldl, Nicole and Gervais, Melissa and Hay, Stephanie and Kushner, Paul J. and Liang, Yu-Chiao and Msadek, Rym and Mudhar, Regan and Sigmond, Michael and Smith, Doug and Sun, Lantao and Yu, Hao},
  title = {Causes and consequences of Arctic amplification elucidated by coordinated multimodel experiments},
  journal = {Communications Earth & Environment},
  year = {2025},
  doi = {10.1038/s43247-025-03052-z},
  url = {https://doi.org/10.1038/s43247-025-03052-z}
}