A multi-hazard spatiotemporal exposure assessment for buildings in Austria

The paper­ presents a nationwide, spatially explicit, object-based assessment of buildings and citizens exposed to riverine flooding, torrential flooding, snow avalanches and multi-hazards in Austria. The assessment was based on two different datasets, (a) hazard information, which provides input for the exposure of the elements at risk, and (b) information on the building stock, which was combined from different spatial data available at the national level. Hazard information was compiled from available local scale hazard maps. The building stock information included information on the location and size of each building, as well as the building category and the construction period and year. In addition, this dataset has an interface with the population register, allowing the number of primary and secondary occupants to be retrieved for each building.

The results of the study challenge the commonly held assumption that exposure levels will inevitably increase as a result of continued population growth and the associated increase in property values. It is shown that this assumption needs to be carefully examined against the background of regional differences in the development of the building stock. While some regions in Austria have experienced asset growth well above the national average, others have experienced below-average growth patterns. These differences reflect not only the different topography of the country, but also the different economic activities and development priorities of the regions. The temporal assessment of exposure has revealed significant differences in the dynamics of exposure to different hazard categories compared to the total building stock.

In conclusion, the property-based assessment presented in this study is proving to be an important and effective tool for conducting nationwide exposure assessments. It provides a robust framework for identifying and addressing one of the most important non-climate risk drivers. Consequently, the insights generated by this approach should play a central role in operational risk management and the formulation of adaptive strategies to enhance resilience in the face of evolving climate change challenges. By revealing the complex dynamics of hazard exposure and asset growth, the study highlights the need to integrate such assessments into long-term planning and policy development.