Granata et al. (2025) Hydrological extremes in the Mediterranean basin: interactions, impacts, and adaptation in the face of climate change

Identification

• Journal: Regional Environmental Change
• Year: 2025
• Date: 2025-07-11
• Authors: Francesco Granata, Senlin Zhu, Fabio Di Nunno
• DOI: 10.1007/s10113-025-02432-7

Research Groups

• Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy
• College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, China

Short Summary

This review synthesizes current knowledge on hydrological extremes (droughts, intense rainfall, floods) in the Mediterranean basin, analyzing their characteristics, trends, interactions, and climate change impacts, while identifying knowledge gaps and recommending integrated adaptation strategies.

Objective

• To systematically evaluate the evolving characteristics, trends, interactions, and climate change impacts of hydrological extremes (droughts, intense rainfall, and floods) in the Mediterranean basin, identify knowledge gaps, and inform effective adaptation and mitigation policies.

Study Configuration

• Spatial Scale: Mediterranean basin (Europe, Asia, Africa), with regional focus on southern, eastern, western, and northern sub-regions, including specific case studies (e.g., Po River basin, Souss-Massa, Greek islands, Cyprus, Maghreb, Spain, France, Italy, Nile Delta, Venetian Lagoon, Causses and Cévennes).
• Temporal Scale: Historical trends (past several decades, e.g., since 1950s, 1961-1990, 1970-1999, 1981-2010) and future projections (up to the end of the 21st century, e.g., 2021-2060, 2041-2070, 2100).

Methodology and Data

• Models used: Synthesis of findings from numerous global and regional climate models (GCMs, RCMs) under various emission scenarios (RCP2.6, RCP4.5, RCP8.5) and Shared Socioeconomic Pathways (SSP1-2.6, SSP5-8.5), including CMIP6 ensemble projections. Drought indices (SPI, PDSI, SMDI, CMI, SDI) and intense rainfall indices (EPI, IDF curves) are discussed.
• Data sources: Comprehensive review of peer-reviewed literature from the past two decades, observational data, climate projections, reanalysis data (e.g., ERA5-Land), satellite data, and reports from IPCC, MedECC, Copernicus Climate Data Store, and the European Environment Agency.

Main Results

• The Mediterranean region is a climate change hotspot, experiencing warming rates exceeding the global average (approximately 1.4 °C since the late 19th century), with projections of 2 to 5 °C warming by 2100 under high-emission scenarios.
• Droughts: Have become more frequent, prolonged, and severe, particularly in the southern and eastern Mediterranean, driven by rising temperatures and reduced winter precipitation (up to 20-30% reduction). This exacerbates water scarcity, wildfire risks, and soil erosion.
• Intense Rainfall: Increased in both frequency and intensity, especially in the western and northern Mediterranean, despite an overall decline in total annual precipitation. These events heighten flash flood risks, particularly in urban areas.
• Floods: Fluvial, urban, and coastal floods are becoming more widespread and severe. Coastal zones face intensified threats from rising sea levels (projected up to 1 meter by 2100 under high-emission scenarios) and storm surges. Compound floods (simultaneous fluvial and coastal) are also increasing.
• Interactions: Hydrological extremes are interconnected; drought-induced soil degradation and vegetation loss amplify subsequent flood severity by reducing water infiltration and increasing runoff.
• Adaptation: Urgent need for integrated water resource management, climate-resilient infrastructure, improved early warning systems, nature-based solutions, and strengthened regional and transboundary cooperation to mitigate escalating impacts.

Contributions

• Provides a comprehensive synthesis of the evolving characteristics, trends, and complex interactions of droughts, intense rainfall, and floods in the Mediterranean basin under climate change.
• Highlights the critical feedback loops between different hydrological extremes (e.g., drought-wildfire-flood cycle) and their amplifying impacts.
• Identifies key knowledge gaps in climate modeling, event prediction, and the understanding of compound events, guiding future research directions.
• Emphasizes the urgent need for integrated, science-informed, and region-specific adaptation and mitigation policies, including nature-based solutions and transboundary water governance.
• Offers valuable insights and lessons for other semi-arid and coastal regions globally facing similar compound climate risks.

Funding

The authors report no financial support received for the creation of this manuscript.

Citation

@article{Granata2025Hydrological,
  author = {Granata, Francesco and Zhu, Senlin and Nunno, Fabio Di},
  title = {Hydrological extremes in the Mediterranean basin: interactions, impacts, and adaptation in the face of climate change},
  journal = {Regional Environmental Change},
  year = {2025},
  doi = {10.1007/s10113-025-02432-7},
  url = {https://doi.org/10.1007/s10113-025-02432-7}
}