There is widespread scientific consensus that the impacts of climate change on human health are already being observed, and are becoming increasingly significant. The U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and the California Department of Public Health (CDPH) all recognize climate change as a significant threat to public health. It is also widely recognized that some people are more vulnerable than others to the impacts of climate change. Where people live, their socioeconomic status, preexisting health conditions and occupation all influence their vulnerability. Contra Costa Health Services (CCHS) is working with CDPH to develop strategies to protect residents from these health threats. This report is an important first step towards that goal.