Insights into social factors shaping coastal flooding vulnerability

The paper investigates factors that could increase households’ vulnerability to coastal flooding. In recent years, social and individual vulnerability has been recognized as an important part of climate risk assessment and management. Climate risks are the result of a combination of hazard, exposure and vulnerability, and including vulnerability indicators in climate risk assessments is a way of acknowledging that the inherent capabilities of different individuals and communities make them susceptible to adverse impacts of climate hazards. The study is part of a large body of literature using social vulnerability indicators to capture which geographical areas are most vulnerable to natural hazards. Often, the indicators used to identify vulnerable areas are chosen based on data availability and are not validated empirically with the actual consequences of natural hazards. Therefore, this study aims to contribute to the literature by investigating the extent to which vulnerability indicators can explain differences in adaptive capacity and the consequences of natural hazards. 

For the study, a survey was sent out to households living in coastal areas of Denmark that were impacted by two different coastal floods in 2023. The survey was distributed to one person per address in the study area (no.=123,000). In total, more than 16,000 people completed the survey, out of which some were directly affected by the floods, some were indirectly affected, and some were not affected at all. After data collection the survey data was combined with detailed micro-level data on demographic, socioeconomic and housing characteristics of the respondents.

First, the complete sample is used to test the empirical relationship between a set of demographic and socioeconomic variables and four different measures of adaptive capacity, controlling also for individual flood risk perception, worry, coping appraisal, flood experience, confidence in authorities and geographic characteristics. Based on the survey, adaptive capacity is in the paper measured by flood awareness, implementation of mitigation measures, and neighborhood ties. This analysis shows what characterizes people with a higher capacity to adapt, who are better prepared prior to a flood, and are better suited to cope with the consequences, potentially minimizing long-term impacts.

Second, a smaller subsample consisting only of respondents who indicated that they had had flooding in their homes is used to analyze the empirical relationship between demographic and socio-economic characteristics and how severely people are impacted by flooding.  This is measured by the renovation time and costs of households, and whether people have experienced different types of stress reactions after the flooding of their home. These results show what characterizes people that suffer most from the consequences of coastal flooding, and thereby which groups are most vulnerable to coastal flooding of their homes.

The results of this study can be used to guide which vulnerability indicators should be used to identify vulnerable areas in Denmark, and other places with high flooding risks, and inform decision-making on climate adaptation that meets a wider range of social and well-being objectives than what can be measured in terms of material damages on buildings and other assets.