Yang et al. (2026) Anthropogenic stresses on sea-level rise and land subsidence triple the future coastal flooding in Shanghai

Identification

• Journal: Regional Environmental Change
• Year: 2026
• Date: 2026-04-06
• Authors: Kexin Yang, Zhiguo Liu, Min Zhang, Jiahong Wen, Linxia Xu, Qing Zhan, Yinpeng Li
• DOI: 10.1007/s10113-026-02579-x

Research Groups

• School of Environmental and Geographical Sciences, Shanghai Normal University, China
• Shanghai Marine Management Affairs Center, Shanghai Marine Bureau, China
• Shanghai Institute of Natural Resources Survey and Utilization, China
• International Global Change Institute, New Zealand

Short Summary

This study quantifies the contributions of anthropogenic activities and natural processes to sea-level rise (SLR) and land subsidence (LSS) on coastal flooding in Shanghai. It reveals that anthropogenic stresses, primarily groundwater extraction and greenhouse gas emissions, will triple the future coastal flooding in Shanghai by 2100 due to amplified combined effects of SLR and LSS.

Objective

• To rigorously quantify and separate the future contributions of natural and human-driven factors (sea-level rise and land subsidence) to coastal flooding in Shanghai.
• To understand how these factors will shape Shanghai’s 200-year return level coastal flood hazards through the middle and end of this century (2050 and 2100).

Study Configuration

• Spatial Scale: Shanghai's urban area (6340 km²), Yangtze River Delta, East China Sea, and Hangzhou Bay. The coastal model uses a 60-meter regular grid, and river channels are represented with 1-kilometer cross-section spacing.
• Temporal Scale: Projections for 2050 and 2100. Baseline year for SLR is 2005, and for flood comparison is 2020. Historical data for ocean model simulations span 1979–2020, and for land subsidence from 1980–2021.

Methodology and Data

• Models used:
  • Coupled 1D–2D numerical hydrodynamic model (MIKE11 for 1D river networks, MIKE21 for 2D coastal propagation).
  • Ocean model (TELEMAC).
  • CLIM systems model framework for global sea-level rise projections.
  • Gaussian Copula function and Generalized Extreme Value (GEV) distribution for joint probability analysis of water levels (WLs) and significant wave heights (SWHs).
• Data sources:
  • Landsat series remote sensing images (USGS) for land cover.
  • Digital Elevation Model (DEM) from Shanghai Surveying and Mapping Institute.
  • Historical seawall height and land subsidence (LSS) data from Shanghai Institute of Survey and Research of Natural Resources.
  • Hydraulic structures data (sluices, seawalls, riverbanks, river channel profiles) from Shanghai Water Authority and Municipal Flood Control Center.
  • Upstream runoff data for the Yangtze and Huangpu Rivers from Shanghai Water Authority.
  • Hydrological and meteorological data (wind and pressure fields) from NOAA and ECMWF.
  • Water level validation data from hourly observations at Hengsha, Zhongjun, and Wusong tide gauge stations.
  • Global sea-level rise projections from IPCC AR6, refined using median sea-level spatial distribution fields from 37 Global Climate Models (GCMs).
  • Historical measured LSS data from six periods between 1980 and 2021.
  • Historical flood maps for urban flood model validation.

Main Results

• Anthropogenic actions (groundwater extraction and greenhouse gas emissions) are projected to increase the inundation areas of 200-year coastal flood hazards in Shanghai by an average of 3 times by 2100.
• The combined effects of SLR and LSS amplify the 200-year flood extent by approximately 2 times more than the sum of their individual effects under a high anthropogenic impact scenario (SSP5-8.5) by 2100.
• SLR becomes the dominant long-term driver, with its contribution to inundated area rising from 8% in 2050 to 36% in 2100 under high anthropogenic impact.
• LSS has a stronger near-term influence, reaching up to 26% higher than SLR before 2050, but its contribution decreases to 8% by 2100.
• By 2100, under the high anthropogenic impact scenario (SSP5-8.5), more than 78% of seawall segments and 53% of riverbanks are projected to be overtopped during a 200-year flood event.
• Anthropogenic pressures increase riverbank overtopping volume by 70% by 2100 compared to 2050, significantly more than the 28% increase for seawalls.
• The human-to-natural ratio for flood extent, considering combined SLR and LSS, increases from 0.6 in 2050 to 4.0 in 2100, highlighting the accelerating dominance of human influence.
• A positive feedback loop exists where flooded areas experience 22% higher land subsidence rates, and coastal wetland submersion extends inland SLR reach by 1 to 8 kilometers.

Contributions

• Provides the first rigorous quantification and separation of future natural and human-driven contributions to sea-level rise and land subsidence impacts on coastal flooding.
• Utilizes a sophisticated coupled 1D-2D hydrodynamic model with high-resolution, spatially differentiated subsidence data and regionally adjusted IPCC AR6 sea-level projections for Shanghai.
• Highlights the "hidden threat" of anthropogenic relative sea-level changes and quantifies their non-linear amplification effect on coastal flooding, which is often overlooked.
• Develops an evidence base for a "dual-axis adaptation" approach, prioritizing immediate LSS restriction for near-term losses and long-term planning for rising seas to secure resilience.
• Emphasizes the critical need for integrated flood risk management strategies over single-hazard approaches for rapidly urbanizing delta cities to achieve UN Sustainable Development Goals.

Funding

• National Natural Science Foundation of China (42171282, 42171080)
• Key Laboratory of Monitoring and Prevention of Land Subsidence, Ministry of Natural Resources’ Open Fund Projects (KLLSMP20230X)
• National Key R&D Program of China (2023YFE0121200)

Citation

@article{Yang2026Anthropogenic,
  author = {Yang, Kexin and Liu, Zhiguo and Zhang, Min and Wen, Jiahong and Xu, Linxia and Zhan, Qing and Li, Yinpeng},
  title = {Anthropogenic stresses on sea-level rise and land subsidence triple the future coastal flooding in Shanghai},
  journal = {Regional Environmental Change},
  year = {2026},
  doi = {10.1007/s10113-026-02579-x},
  url = {https://doi.org/10.1007/s10113-026-02579-x}
}