Azhar et al. (2025) Comprehensive portfolio of adaptation measures to safeguard against evolving flood risks in a changing climate

Identification

• Journal: Communications Earth & Environment
• Year: 2025
• Date: 2025-10-17
• Authors: Mohammed Azhar, Bergen L. Kane, Farshid Vahedifard, Amir AghaKouchak
• DOI: 10.1038/s43247-025-02779-z

Research Groups

• Department of Civil and Environmental Engineering, Tufts University, Medford, MA, USA
• Institute for Water, Environment, and Health (UNU-INWEH), United Nations University, Richmond Hill, ON, Canada
• Department of Civil & Environmental Engineering, University of California, Irvine, CA, USA
• Department of Earth System Science, University of California, Irvine, CA, USA

Short Summary

This review compiles and critically analyzes a comprehensive portfolio of 39 flood adaptation measures, classifying them into four groups and evaluating their advantages, disadvantages, co-benefits, and tradeoffs to inform successful, socially just, practically feasible, and technically sound adaptation strategies against evolving flood risks in a changing climate.

Objective

• To compile a comprehensive portfolio of 39 flood adaptation measures, classifying them into infrastructural/technological, institutional, behavioral/cultural, and nature-based categories.
• To evaluate each adaptation measure for its advantages, disadvantages, co-benefits, and tradeoffs.
• To identify key decision-making attributes (socially just, practically feasible, and technically sound) for successful adaptation strategies.
• To highlight research gaps and provide recommendations for future transdisciplinary approaches to developing and implementing climate-resilient and equitable flood adaptation strategies.

Study Configuration

• Spatial Scale: Global (literature review covers global contexts, regional distribution analysis), with specific examples from the U.S., Europe, and Asia.
• Temporal Scale: Literature review focused on 2018–2024, with foundational works before; analysis of flood adaptation evolution from pre-1950s to present; consideration of future climate projections (e.g., global warming reaching or exceeding 1.5 °C by 2040, sea level rise of 0.3 to 2.0 meters by 2100).

Methodology and Data

• Models used: The study discusses various models and frameworks, including climate models (for projections), hydrological and hydraulic models (for flood forecasting/impacts), Dynamic Adaptive Policy Pathways (DAPP), Dynamic Adaptive Policy Pathways for multi-risk (DAPP-MR), Adaptation-Tipping-Point (ATP), and Adaptive Delta Management.
• Data sources: Scoping review of 173 peer-reviewed journal articles, systematic reviews, case studies, and policy reports. Key sections of the IPCC 6th Assessment Report. Systematic searches using Google Scholar.

Main Results

• A comprehensive portfolio of 39 flood adaptation measures was compiled, categorized into 18 Infrastructural/Technological, 9 Institutional, 2 Behavioral/Cultural, and 10 Nature-Based strategies. Each measure was critically analyzed for its advantages, disadvantages, co-benefits, and tradeoffs.
• The evolution of flood adaptation measures was identified across four broad eras, showing a shift from early structural modifications towards more recent soft, community-centered, and nature-based solutions.
• Three foundational attributes for successful flood adaptation strategies were proposed: social justice, practical feasibility, and technical soundness.
• Key research gaps were identified, including the need for integrating qualitative and quantitative approaches, bridging policy fragmentation, clarifying evolving risk thresholds, enhancing site-specific decision-making, leveraging emerging technologies (AI, Earth observations), and incorporating vulnerability attributes for equitable adaptation.
• Infrastructural/Technological measures were the most frequently represented in the reviewed literature (n=99), followed by Nature-Based (n=68), Institutional (n=48), and Behavioral/Cultural measures (n=10).
• Most reviewed studies focused on North America, Northern and Western Europe, Eastern Asia, and South Asia, indicating a need for greater inclusivity and geographic diversity in future research.

Contributions

• Provides the first comprehensive portfolio of 39 flood adaptation measures, critically analyzed for their multifaceted impacts, serving as a unique reference for decision-makers.
• Offers a novel historical perspective on the evolution of flood adaptation strategies, identifying four distinct eras and highlighting the shift towards integrated, multi-dimensional approaches.
• Proposes a foundational multi-attribute decision-making framework (socially just, practically feasible, technically sound) to guide the selection and implementation of effective and equitable adaptation strategies.
• Identifies and articulates critical research gaps and opportunities, emphasizing the need for transdisciplinary collaboration and integrated approaches to advance climate-resilient flood adaptation globally.

Funding

• National Science Foundation (NSF) under Grants No. CMMI-2401545 and CMMI-2332263.
• Caltrans Agreement No. 74A1414.

Citation

@article{Azhar2025Comprehensive,
  author = {Azhar, Mohammed and Kane, Bergen L. and Vahedifard, Farshid and AghaKouchak, Amir},
  title = {Comprehensive portfolio of adaptation measures to safeguard against evolving flood risks in a changing climate},
  journal = {Communications Earth & Environment},
  year = {2025},
  doi = {10.1038/s43247-025-02779-z},
  url = {https://doi.org/10.1038/s43247-025-02779-z}
}