Sea level rise risk index in Portugal at the parish level for baseline, 2040, 2070 and 2100 based on SSP scenarios

Sea level rise risk index in Portugal at the parish level for baseline, 2040, 2070, and 2100 based on SSP scenarios This dataset provides a high-resolution, integrated spatial assessment of sea-level rise (SLR) risk at the civil parish level across mainland Portugal's entire coastline. The dataset covers 138 civil parishes distributed across 52 coastal municipalities. The compiled database delivers normalised index values (theoretically ranging from 0 to 1) for the three core dimensions of risk, aligning with the conceptual frameworks proposed by the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Office for Disaster Risk Reduction (UNDRR): Hazard (Prefix A_): Evaluated based on the physical extent of floodable coastal areas, incorporating local tides, storm surges, wave run-up, and projected morphodynamic shoreline retreat. Exposure (Prefix EXP_): Calculated using the georeferenced location of residential buildings and dasymmetric downscaling of census population data. Social Vulnerability (SV): Assessed as a function of population criticality (intrinsic socio-demographic drivers) and local support capability (infrastructural and service redundancy to recover from disasters). To support long-term spatial planning and proactive coastal adaptation, the dataset is structured multi-temporally: Baseline Reference: Year 2011. Future Planning Horizons: Projected mid-term (2040 and 2070) and long-term (2100) horizons. Climate Scenarios (Shared Socioeconomic Pathways - SSP): Future assessments are modelled under three contrasting emission pathways: SSP1 (SSP1-2.6): High-sustainability, low-emission pathway. SSP2 (SSP2-4.5): An intermediate, "middle-of-the-road" scenario. SSP5 (SSP5-8.5): High-emission, fossil-fuel-intensive development representing the worst-case scenario. The attributes in the tabular data and the corresponding geospatial shapefile are organised as follows: Geographic Identifiers Identifiers include the administrative parish code, parish name, municipality, and the corresponding coastal sedimentary cell (physical divisions of the Portuguese coast). Hazard Index (Prefix A_ / Variable A_SSP[Scenario]_[Year]) Measures the local physical propensity to coastal flooding. Inundation extents are calculated based on extreme water levels (astronomical tide, storm surge, and wave run-up) combined with historical coastal retreat rates. To mitigate the statistical influence of highly skewed distributions, a natural logarithm is applied to the raw flooded areas (in square kilometres) before scaling to a range. Key fields include: A_SSP2_70n (2070, SSP2), A_SSP2_100 (2100, SSP2), A_SSP5_40n (2040, SSP5), A_SSP5_70n (2070, SSP5), and A_SSP5_100 (2100, SSP5). Exposure Index (Prefix EXP_ / Variable EXP_SSP[Scenario]_[Year]) Evaluates the volume of residential assets and population intersecting projected flood zones. For future scenarios, the baseline 2011 spatial distribution of buildings and population is overlaid with the simulated flood footprints of each scenario. A natural logarithm of the building count and estimated resident population is calculated to reduce the impact of extreme values. Key fields include: EXP_2011 (Baseline exposure), EXP_SSP1_4 (2040, SSP1), EXP_SSP1_7 (2070, SSP1), EXP_SSP1_1 (2100, SSP1), along with equivalent projections for SSP2 and SSP5 (e.g., EXP_SSP5_1 for 2100 exposure under the worst-case scenario). Social Vulnerability Index (SV) Represents the inherent socio-economic susceptibility of local populations, computed with a Principal Component Analysis (PCA) using 15 robust socio-demographic variables derived from national census data. Social vulnerability is held constant across all future timelines to isolate the physical impacts of climate hazards and changing exposure footprints. Sea Level Rise Risk Index (Prefix R_ / Variable R_SSP[Scenario]_[Year]) Computed as a weighted geometric mean of the three individual risk dimensions: SLR Risk = Hazard1/3 x Exposure 1/3 x Social Vulnerability 1/3 The index scores theoretically range between 0 and 1. To prevent a value of zero in one dimension from nullifying the final risk score, any absolute zero values are replaced with a minimal millesimal value (one unit lower than the lowest non-zero score recorded in that dimension), preserving the overall ranking. Key fields include: R_2011 (Baseline risk) and future risk indices spanning 2040, 2070, and 2100 across the SSP1, SSP2, and SSP5 pathways (e.g., R_SSP1_40 to R_SSP5_100). This dataset corresponds to the Supplementary Material 1: Sea level rise hazard, exposure, social vulnerability, and risk indices for coastal parishes of mainland Portugal (Baseline 2011 & Future Scenarios 2040, 2070, 2100), published in Discover Hazards (Pereira et al., 2026). The outputs are available in shapefile format, along with the lyr files and a table with field descriptions. This dataset is an output of the research project High Waters – Assessment of exposure scenarios and social vulnerability to sea level rise for the sustainable use of the territory (Reference: EXPL/GES-AMB/1246/2021). The project was funded by national funds through the FCT – Fundação para a Ciência e a Tecnologia, I.P.. Official Project Website: https://projetohighwaters.wixsite.com/high-waters