The World Health Organization projects climate change will adversely affect health significantly over the next several decades. Some health effects of climate change are already being felt in the United States, according to assessments by the National Research Council, U.S. Global Change Research Program (USGCRP), and others. Since the federal government is the nations largest purchaser of health care services, federal health care expenditures could increase in future years due to climate-related impacts. This book addresses federal activities to enhance understanding about the risks climate change poses to public health; federal resources used by selected states and localities to address these risks; and challenges states and localities face and actions federal agencies could take to mitigate them. This book also provides a suggested sequence of steps that health departments can undertake to assess such health vulnerabilities associated with climate change.