The past and future in understanding the health risks of and responses to climate variability and change.

Climate change and health was established as a formal field of endeavor in the early 1990s, with the number of publications increasing since the mid-2000s. The key findings in assessment reports from the Intergovernmental Panel on Climate Change in 1995, 2001, 2007, and 2014 indicate the progress in understanding the magnitude and pattern of the health risks of a changing climate. The assessments maintained a similar structure, focusing on assessing the state of knowledge of individual climate-sensitive health outcomes, with confidence in the key findings tending to increase over time with greater understanding. The knowledge base is smaller than for other key sectors (e.g., agriculture) because of limited research investment in climate change and health. Vulnerability, adaptation, and capacity assessments can inform prioritization of the significant research gaps in understanding and managing the health risks of a changing climate; filling these research gaps would provide policy- and decision-makers with insights to increase short- and longer-term resilience in health and other sectors. Research needs include to understand how climate and development pathways could interact to alter health risks over time, better understand upstream drivers of climate-sensitive health outcomes, project aggregate health impacts to understand the breadth and depth of challenges that may need to be managed at geographic scales of interest, and project the time of emergence of changes in the geographic range and intensity of transmission of infectious diseases and other climate conditions. Engagement with other sectors is needed to ensure that their mitigation and adaptation activities also promote and protect health and take the health sector's needs into account. Making progress in these areas is critical for protecting the health of future populations.