Community Vulnerabilities to Climate Change

Program California Environmental Health Tracking Program

Director Paul English


With financial support from the Association of State and Territorial Health Officials (ASTHO), CEHTP developed a tool to screen communities for vulnerability to climate change using a relatively simple, transparent, and flexible method.  This tool was piloted for Los Angeles and Fresno Counties.  The research builds upon an Environmental Justice Screening Method (EJSM) developed by the University of Southern California’s Program for Environmental and Regional Equity.


The public health risks from climate change vary across California’s communities and among individuals within these communities.  It is essential to know which communities or populations are most vulnerable to climate change in order to identify strategies to reduce their risk and improve community resiliency.  Advanced planning will be central to preventing illness and death.  A first step in planning is to understand the risks faced by different communities.

The California Environmental Health Tracking Program (CEHTP) utilized an existing environmental justice screening method (EJSM) and adapted it to examine climate change vulnerability among communities within two counties likely to experience substantial climate change impacts—Los Angeles and Fresno Counties.  The EJSM enables mapping of population risk to climate change at the census tract level.  CEHTP used this and incorporated metrics associated with climate change impacts and a community’s adaptive capacity.


Drawing on data from a variety of public sources, census tract level metrics were calculated for:

  • air conditioning (AC) ownership
  • land cover characteristics (tree canopy and impervious surfaces)
  • access to transportation (transit and household car access)
  • social vulnerabilities (elderly living alone)
  • flood risk
  • wildfire risk
  • sea level rise

Each metric was ranked into quintile scores for each census tract.  These scores were summed for each tract and re-ranked to obtain cumulative quintile scores indicating population vulnerability to climate change.  The cumulative quintile scores for population vulnerability to climate change were also compared and added to cumulative impact scores from the EJSM, developed by Sadd et al.


Final climate change vulnerability scores by census tract for Los Angeles and Fresno counties were generally higher in urban areas. In Los Angeles County, areas of risk were also fund along coastal areas, largely from risks due to sea level rise, but also partially attributable to poor public transit, wildfire risk, and a greater proportion of elderly living alone. The western portion of Fresno County was also identified as having high vulnerability to climate change threats, primarily due to low air conditioner and car ownership, as well as low tree canopy average.

In addition, African Americans and Latinos were more likely to live in high risk areas compared to Whites.  Clear income disparities were also found, with the lowest income households living in areas of greater climate change vulnerability.

See Maps of community vulnerabilities to climate change.


  • Occidental College
  • Pacific Institute
  • University of California, Berkeley—School of Public Health
  • University of Southern California—Program for Environmental and Regional Equity