The Science Basis for Heat-Health Early Warning Systems

Climate records from NOAA's National Centers for Environmental Information show that the number of unusually hot summer days - exhibiting both higher highs and higher lows - for the contiguous United States has increased over the past four decades. These heat extremes often occur as multi-day heat waves, and have affected communities around the globe - from the Chicago metro area in 1995 to Europe in 2003 and the Indian subcontinent in 2015. Moreover, projections from the most recent National Climate Assessment indicate that the number of extremely hot days will likely increase throughout the 21st century.

These heat waves are known to be accompanied by spikes in heat-related mortality and morbidity, and such health outcomes are exacerbated by heat-related air pollution, energy system failures, and other human and environmental factors. Since the deadly heat waves of the 90's, many cities and states, as well as federal agencies such as NOAA, CDC, and FEMA have focused on increasing awareness and early warning for these extremes. An integrated, end-to-end, research-based approach is needed to consolidate these efforts - informed by cooperatively developed and sustained environmental intelligence from the earth and atmospheric sciences, public health, and social science communities, and guided by well-defined requirements from a diverse base of constituents.

Information on heat extremes and variability that spans the weather-climate continuum can be projected and communicated as part of an integrated and adaptive information system that addresses emerging risks and informs longer-term resilience strategies. Such a system can engage vulnerable individuals in a community of practice that is resilient to the growing threat of extreme heat - an approach with a proven track record in efforts like NIDIS and affiliated NOAA research programs like Regional Integrated Sciences and Assessments (RISAs) and the Modeling Analysis Predictions and Projections (MAPP) programs.

In this presentation we explore the scientific basis for early warning as it pertains to the development of a heat-health information system. We demonstrate that skillful seamless prediction of heat extremes is possible, and that there is clear evidence that such information spanning the weather-climate continuum can enhance resilience to extreme heat. Based on these findings, we advocate for the development of a National Integrated Heat Health Information System (NIHHIS) in the United States.

The intent of this session is to lay the scientific justification for developing such a system. It includes a consideration of current capabilities in extreme heat prediction and projection, an exploration of future research needs in the atmospheric and public health communities, and a roadmap for the implementation of the NIHHIS.