The Epidemiologic Silver Lining of Climate Change
The new report,1 part of the US Global Change Research Program’s sustained National Climate Assessment process, is the result of the efforts of more than 100 experts to synthesize the most current existing scientific literature on the relationship between climate change and health outcomes across a comprehensive set of climate-driven exposure pathways. The report also presents, for the first time, quantitative estimates of future health risks and changes in exposures for five different health impact areas. The nearly 3-year process of creating the report included multiple stages of both public and federal agency review, as well as review by a panel of experts assembled by the National Academy of Sciences.
Framed by an introduction that provides context for existing climate and health trends and a closing discussion focused on populations of concern, the report examines seven different types of health impacts: effects of temperature extremes (particularly heat), poor air quality, extreme events (and resulting disasters), vector-borne diseases, water-related illness, food safety and nutrition, and mental health impacts. Unlike previous assessments, the report breaks new ground in emphasizing mental health impacts and food quality and nutrition.
While the report stresses that all Americans are exposed to climate change risks, it also emphasizes that there are important differences among people and communities in vulnerability. The report defines vulnerability as a combined measure of a person or population’s exposure to a climate stressor, their sensitivity, or the degree to which they are affected, and their adaptive capacity, or ability to respond to such stressors. Hence, vulnerability is influenced by a variety of factors (social, genetic, behavioral) through changes in relative exposure, sensitivity, and adaptive capacity to climate change. The report also defines the related concept of resilience as the long-term ability to prepare for, recover from, and adapt to climate impacts. As epidemiologists are acutely aware, vulnerability and resilience are closely associated with social determinants of health, such as income, education, age, and other factors. Risks are compounded when these determinants interact or occur in clusters in people or populations to exacerbate the effects of environmental health exposures. For this reason, the report devotes a lengthy initial discussion of social determinants, and integrates these considerations throughout the individual topic chapters.
Although the report was not intended to be a research needs assessment, each chapter identifies examples of research data or methods gaps that may warrant further traditional epidemiological investigation or possibly collaborative multidisciplinary approaches. Taken together, these discussions offer a rich vein of inquiry for epidemiologists to mine. In this article, we draw strongly, although not verbatim, from the needs identified by the assessment authors to illustrate potential opportunities for epidemiological input to a number of research areas.