Hermans et al. (2026) Future Changes in the Annual Sea‐Level Cycle

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

Identification

• Journal: Earth s Future
• Year: 2026
• Date: 2026-01-01
• Authors: Tim H. J. Hermans, Julius Busecke, Roderik S. W. van de Wal
• DOI: 10.1029/2025ef006735

Research Groups

Information not available from the abstract.

Short Summary

This study evaluates the historical performance of the annual sea-level cycle (ASLC) in CMIP6 models and projects future changes, finding a multi-model median increase of 7.9% in ASLC range by 2071–2100 under a high emissions scenario, with significant implications for seasonal sea-level projections.

Objective

• To address limitations in existing annual sea-level cycle (ASLC) projections, including the exclusion of the inverse-barometer effect, uncertainty due to internal variability, regional focus, and lack of extensive historical model evaluation.
• To evaluate the historical ASLC performance of climate models used for projections, specifically within the Coupled Model Intercomparison Project 6 (CMIP6) ensemble.
• To project future changes in the ASLC range and peak month for 2071–2100 under various emissions scenarios, incorporating the inverse-barometer effect.
• To quantify how ASLC changes translate to differences between seasonal and annual mean sea-level changes and their influence on projections of hazards and impacts tied to specific seasons.

Study Configuration

• Spatial Scale: Global, with specific focus on tide-gauge locations and regions including Northwestern Europe, the Mediterranean, Asia, and the North Pacific.
• Temporal Scale: Historical evaluation; future projections for the period 2071–2100.

Methodology and Data

• Models used: Large ensemble of simulations from the Coupled Model Intercomparison Project 6 (CMIP6).
• Data sources: Observations (for comparison and evaluation of historical ASLC in climate models).

Main Results

• Four specific CMIP6 climate models were identified as performing particularly poorly compared to observations regarding the historical ASLC.
• Excluding these poorly performing models, the multi-model median projections for 2071–2100 indicate an average increase in the ASLC range at tide-gauge locations of 7.9% under a high emissions scenario.
• Changes under lower emissions scenarios show similar spatial patterns but have a smaller magnitude.
• Regions projected to experience above-average changes in ASLC range include Northwestern Europe, the Mediterranean, Asia, and the North Pacific.
• The inverse-barometer effect contributes substantially to the total ASLC changes in several regions.
• Median projected shifts in the peak month of the ASLC are mostly small, though substantial uncertainties suggest larger changes cannot be excluded.
• ASLC changes lead to differences between seasonal and annual mean sea-level changes of up to 5.4 cm under the highest emissions scenario.
• Sea-level projections that exclude seasonal changes can under- or overestimate total sea-level change in specific seasons by more than 8%.

Contributions

• Provides a comprehensive assessment of future annual sea-level cycle (ASLC) changes by addressing key limitations of previous projections, including the explicit inclusion of the inverse-barometer effect and a robust multi-model ensemble approach.
• Conducts an extensive evaluation of historical ASLC performance across a large ensemble of CMIP6 models, identifying poorly performing models.
• Quantifies the regional and global projected changes in ASLC range and peak month under different emissions scenarios.
• Highlights the significant impact of ASLC changes on seasonal sea-level projections, demonstrating how neglecting seasonal variations can lead to substantial under- or overestimation of total sea-level change in specific seasons, which is critical for hazard and impact assessments.

Funding

Information not available from the abstract.

Citation

@article{Hermans2026Future,
  author = {Hermans, Tim H. J. and Busecke, Julius and Wal, Roderik S. W. van de},
  title = {Future Changes in the Annual Sea‐Level Cycle},
  journal = {Earth s Future},
  year = {2026},
  doi = {10.1029/2025ef006735},
  url = {https://doi.org/10.1029/2025ef006735}
}