The future health costs associated with predicted climate change-related events such as hurricanes, heat waves, and floods are projected to be enormous. This article estimates the health costs associated with six climate change-related events that struck the United States between 2000 and 2009. The six case studies came from categories of climate change-related events projected to worsen with continued global warming-ozone pollution, heat waves, hurricanes, infectious disease outbreaks, river flooding, and wildfires. We estimate that the health costs exceeded $14 billion, with 95 percent due to the value of lives lost prematurely. Actual health care costs were an estimated $740 million. This reflects more than 760,000 encounters with the health care system. Our analysis provides scientists and policy makers with a methodology to use in estimating future health costs related to climate change and highlights the growing need for public health preparedness. C limate change endangers public health. Rising atmospheric temperatures increase the frequency, intensity, duration, and geographic extent of heat waves, air pollution episodes, wildfires, activity of infectious disease vectors, rising sea levels, storms, extreme rainfall, and flooding. 1,2Prior studies have estimated future health costs related to climate change.3-6 However, these figures are not specific enough to form the basis of health policy decisions. No US study has evaluated specific health outcomes associated with a set of events related to climate change. 7,8 There is currently no well-accepted structure for quantifying the costs of the human health effects of climate change, in part because of the challenges of identifying comprehensive health impact data and a lack of consensus on health cost valuation methods. Some methods estimate health costs in monetary terms; others use physical units such as the number of lives saved or the number of cases of illness avoided. Another approach is to use indicators such as quality-adjusted life-years, a measure that incorporates both mortality and morbidity effects. 9Estimating the health costs of climate change is important for informing health policy decisions. Evaluating health-associated costs using a common method and then aggregating the costs can allow us to compare the various effects of climate change-once normalized, to account for geographic and other differences-with regard to magnitude or importance. Case studies can also help us gauge the progress of climate change-related health preparedness policies over time under different adaptation scenarios. 9These scenarios present a range of possible regional climate effects, varying health vulnerabilities, and changing social and economic conditions that can help or hinder these policies' effectiveness.The objective of this study was to provide a cost calculation of health effects associated with events related to climate change over the past