Climate Vulnerability Index
What is the Climate Vulnerability Index?
In 2023, the county council produced the Climate Vulnerability Index (CVI) in partnership with the University of Brighton. The tool was updated in 2025 to offer a more detailed look at vulnerabilities across West Sussex through new environmental data and a more advanced methodology.
The CVI represents a unique geospatial mapping tool among UK local authorities that considers the relationships between social and environmental vulnerabilities.
The tool analyses social, economic and environmental data to identify which areas of the county are more vulnerable to climate change and why.
The CVI looks at population, climate risks and how exposed communities are to those risks. This gives a complete picture of climate change vulnerability and helps guide adaptation efforts.
The CVI uses data from the UK Census, the Indices of Multiple Deprivation and public datasets from the Met Office, DHLUC, Defra and other sources.
The Climate Vulnerability Index has been developed through a partnership between West Sussex County Council and the University of Brighton. It uses a unique indexing methodology to determine relative levels of climate vulnerability across the county.
We request that any extraction and use of the data derived from this indexing methodology be attributed to West Sussex County Council.
We welcome your feedback by emailing cvi@westsussex.gov.uk.
What does the CVI show?
The CVI includes data for every Lower Layer Super Output Area (LSOA) in West Sussex. To calculate climate vulnerability scores, we compare each LSOA to others across all data layers. We then turn those rankings into a single score for climate vulnerability. We use the same method to calculate scores for heat and flood vulnerability.
These scores show which communities may be more at risk from climate change, based on social factors, climate threats and how exposed they are to those threats.
The CVI doesn’t just show overall climate vulnerability - it also highlights specific risks like flooding and extreme heat. This helps users see which climate threats affect their communities most and explore what factors contribute to those vulnerability scores.
The tool includes all the individual data layers that make up the index. These cover population details like income, health and age, as well as environmental risks such as heat inequality, flood risk, poor air quality and limited access to green spaces.
Having access to this wealth of data from multiple sources in an easily accessible and visual format improves our ability to support our communities and prevent future service disruption.