Climate change is driving changes in weather patterns that have significant effects on human health and behavior through multiple direct and indirect pathways, including through rising temperatures. Extreme heat and more frequent and severe heat waves are leading causes of weather-related morbidity and mortality in the United States and globally (Smith et al 2014), with certain populations such as the elderly, people with chronic diseases, and outdoor workers at elevated risk (Boeckmann and Rohn 2014; Sheridan and Allen 2015). Morbidity and mortality during periods of extreme heat is preventable through a number of measures (e.g., modification of exposure). One intervention shown to reduce the adverse health effects of heat waves is heat early warning systems. Heat warning systems provide health system planners with meteorological predictions that allow them to prepare for periods of extreme heat and inform the public about appropriate protective behaviors. Heat early warning systems are commonly accompanied by heat action plans that include public communications, establishment of cooling centers and other protective measures for vulnerable populations, and training and preparation of key stakeholders and first responders (Hess and Ebi 2016). The introduction of heat early warning systems spread following the 1995 Chicago heatwave, and since that time have been implemented at the city, state, and national level in the US and internationally (Lowe et al 2011).
Variation in the content and implementation of heat warning systems makes evaluation of these interventions challenging; however, evidence from the US, Australia, China, and Europe suggests that having early warning systems in place reduces heat-related morbidity and mortality (Bassil and Cole 2010; Ebi et al 2004; Boeckmann and Rohn 2014; Nitschke et al 2016; Toloo et al 2013). Many health agencies including the World Health Organization have provided guidance to state and local jurisdictions on the design and implementation of heat early warning systems (McGregor et al 2015). Despite promising evidence, many localities and countries at high risk for heat waves do not have warning systems in place to promote effective response to extreme heat or heat waves (e.g., Bittner et al 2014; Sheehan et al 2017). The results are deadly, for example, the 2015 heat wave in India resulted in over 2000 deaths, and the 2003 European heatwave resulted in over 30,000 excess deaths. It is estimated that by 2100, between 50 and 74% of the world’s population will be exposed to temperatures associated with high risk of heat-related mortality at least 20 days each year (Mora et al 2017). Therefore, developing a better understanding of the components of effective heat early warning systems and the strategies for scaling up implementation of these systems to reach vulnerable populations is essential for preventing an increase in heat-related mortality as the world undergoes increasingly rapid climatic change.
References
· Bittner M et al (2014). Are European countries prepared for the next big heat wave? European Journal of Public Health, 24(4): 615 – 619.
· Boeckmann M and I Rohn (2014). Is planned adaptation to heat reducing heat-related mortality and illness? A systematic review. BMC Public Health, 14:1112.
· Ebi KL et al (2004). Heat watch/warning systems save lives: Estimated costs and benefits for Philadelphia 1995 – 98. Bulletin of the American Meteorological Society, 9(2).
· Lowe D, KL Ebi and B Forsberg (2011). Heatwave early warning systems and adaptation advice to reduce human health consequences of heatwaves. International Journal of Environmental Research and Public Health, 8(12): 4623-4648.
· McGregor GR et al (2015). Heatwaves and Health: Guidance on Warning-System Development. World Health Organization and World Meteorological Organization.
· Mora C et al (2017). Global risk of deadly heat. Nature Climate Change, 7:501 – 506.
· Nitschke M et al (2016). Evaluation of a heat warning system in Adelaide, South Australia, using case-series analysis. BMJ Open, 6(7).
· Sheehan M et al (2017). Integrating health into local climate response: Lessons from the US CDC Climate-Ready States and Cities Initiative. Environmental Health Perspectives, 125(9).
· Sheridan SC and MJ Allen (2015). Changes in the frequency and intensity of extreme temperature events and human health concerns. Current Climate Change Reports, 1(3): 155 – 162.
· Smith KR et al (2014). Human health: impacts, adaptation, and co-benefits. In: Climate Change 2014: Impacts, Adaptation and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.
· Toloo G et al (2013). Are heat warning systems effective? BMC Environmental Health, 12:27.
· Toloo G et al (2013). Evaluating the effectiveness of heat warning systems: systematic review of epidemiological evidence. International Journal of Public Health, 58(5):667 – 681.