Integrated implementation and validation of the ICARIA Risk Assessment Framework and Decision Support System (DSS) applied in the Southern Aegean region

This paper presents the results of the ICARIA Horizon Europe risk-assessment framework and web-based Decision Support System (DSS) that were applied in the Southern Aegean Region (Greece) to quantify single- and multi-hazard climate risks (wildfire, heatwave, extreme wind) and to assess adaptation under historical and future climates (SSP1-2.6, SSP5-8.5). The study integrates high-resolution hazard layers (5 km Fire Weather Index, downscaled temperature extremes), satellite-derived land surface temperature (30 m LST for building exposure), asset-level exposure and vulnerability, and probabilistic event-tree-based multi-hazard modelling, and was tested with stakeholders in Rhodes and Syros. Results show increases in wildfire and ecological multi-hazard risk: ecological high-risk (categories 4–5) areas expand by ~10–15%, and economic high-risk zones by ~5–8%.

On Rhodes, very high fire-weather days (FWI > 70) rise under SSP5–8.5, and the central mountains shift into the highest ecological risk (category 5). A multi-hazard indicator (FWI > 80, Tmax > 30 °C, wind > 10.8 m/s) identifies persistent future hotspots. The 2023 Rhodes wildfire (~17,600 acres burned; ~€1.29 M electricity, ~€400 k water damage, ~2500 livestock and ~60,000 olive trees lost; ~19,000 evacuees) supports model projections. Adaptation substantially reduces risk. Vegetation substitution (e.g., Ceratonia siliqua, low-flammability stands) cuts category-5 ecological areas by ~30–32% and high-risk economic areas by ~20% (single hazard) and ~28–34% (multi-hazard). On Syros, retrofitting 1980–2010 buildings reduces top-risk classes (4–5) by ~25–35% and lowers thermal-stress exposure. Stakeholder trials found the DSS user-friendly and useful for comparing business-as-usual versus adaptation scenarios and for strategic planning, while highlighting needs for broader hazard coverage and continued support.