Impacts of global climate change on community health
California is a national leader in innovative programs designed to reduce greenhouse gas emissions. However, no matter how quickly we cut our emissions, some climate change will still occur. From sea level rise to an increase in heat waves, climate change will be a new and challenging reality for all Californians.
Climate change is nearly always discussed as a global issue, and we often lose sight of the fact that its impacts will be felt in a very real way in our own communities. For example, the following scenarios are predicted to occur:
- Air quality will worsen, contributing to increased asthma attacks
- Heat waves will become more severe and more frequent, putting both people and animals at risk
- Flooding will worsen, increasing risk of food and water contamination, transmission of infectious diseases, displacement of families and communities, and disruption of basic services
- Wildfires will increase, degrading air quality and potentially destroying entire neighborhoods
Given the wide range of problems that climate change will pose in California, it is essential that we start preparing today. Identifying communities at greatest risk is a necessary step in efficiently employing limited resources to protect public health.
Who will be most affected by climate change?
Exactly who will be most affected by climate change is a complex question. Multiple factors may place one community at greater risk, and these factors can shift over time. Factors that influence a community's vulnerability to climate change include:
- Risk of exposure to environmental impacts of climate change (e.g., living near water increases risks from flooding)
- Capacity to adapt effectively to a changing environment (e.g., establishing extensive tree canopies in urban neighborhoods increases their ability to withstand heat waves)
- Sensitivity to climate change events (e.g., elderly people face much graver health risks during a heat wave)
We know that climate change is occurring, but it will not be easy to forecast how these changes will unfold over the coming decades. With so many complexities and limited data available, how do we weigh the risks?
CEHTP Project: Screening for vulnerable communities
The California Environmental Health Tracking Program (CEHTP), with funding from the Association of State and Territorial Health Officials, has completed a project to develop and pilot methods to screen for those communities likely to be most vulnerable to a changing climate. A screening tool is not intended to show future impacts with absolute certainty, but rather to highlight areas of greatest concern. The results from the screening can facilitate community discussions and help local officials make difficult planning decisions to help communities prepare for and mitigate the potential impacts of climate change.
Unlike previous research that has focused on large geographic regions, such as counties or states, or on a single facet of climate change, such as risks to extreme heat events, the CEHTP screening tool considers a community's risk of exposure, adaptive capacity, and population sensitivity-all at the census tract level. CEHTP's methods incorporate data on predicted sea level rise, flood risk, wildfire risk, proportion of elderly people living alone, household car access, tree canopy coverage, extent of impervious surfaces such as asphalt or concrete, air conditioner ownership, and access to public transit. These methods were adapted from the Environmental Justice Screening Method, developed by Sadd et al.1
The screening tool was piloted in two counties likely to face considerable challenges from climate change: Los Angeles and Fresno.
Results Show Disproportionate Risks
The maps below show the results from the screening tool. The final vulnerability scores are displayed by census tract. The full summary of the project results are available on the CEHTP website. View the Climate Change Vulnerability Report for a full description of the methodology and for maps of each dataset used in the screening tool.
We found that climate change risks are not equal across Fresno and Los Angeles Counties.
- Geographic disparities: Overall, community vulnerability to climate change tended to be greater in urbanized areas, such as downtown Los Angeles and downtown Fresno.
- Racial disparities: African Americans and Latinos were more likely to live in-high risk areas compared to Whites.
- Income disparities: Median income in the most vulnerable areas of Los Angeles County was 40% lower than median income in the least vulnerable areas. In Fresno County, this disparity was even greater, with median income 55% lower in the most vulnerable areas compared to the least vulnerable areas.
Clearly, climate change risks are not equal across the state or within individual counties. With this pilot project, CEHTP has taken a first step in understanding which communities are at the greatest risk from climate change. We hope this work can be expanded statewide so that state and local-level policies, budgets, and regulations can address the rapidly evolving reality of climate change in California. In addition, we hope to have the opportunity to validate our findings by working with communities, community-based organizations, and local health departments to ground-truth our data. We will continue to contribute to climate change science and research, in hopes of preparing our communities for generations to come.
To learn more about the impacts of climate change on public health in California, visit:
1 Sadd JL, Pastor M, Morello-Frosch R, Scoggins J, Jesdale B. "Playing it Safe: Assessing Cumulative Impact and Social Vulnerability through an Environmental Justice Screening Method in the South Coast Air Basin, California". International Journal of Environmental Research and Public Health. 2011. 8:1441-1159