Progress in extreme heat management and warning systems: A systematic review of heat-health action plans (1995-2020)

In recent decades, rising trend in the number of heat waves (HWs) has exacerbated the risk of heat-related mortality and morbidity. The frequent deadly HWs precipitated a multitude of national and sub-national heat-health prevention and research efforts. In 2008, the WHO Regional Office for Europe developed and published guidance on heat-health action plans (HHAPs). This provided a blueprint for countries to design heat-related prevention efforts. Since then, a large corpus of new evidences and implementation experiences has emerged around adaptive measures, alert systems and urban planning interventions. The present study conducts a systematic review to critically assess the advent and development of HHAPs with a special focus on its integration with urban planning policies. It reviews the concept of threshold, indicators for heat event determination and measurement of HWs to understand trigger setting mechanisms. The results show that implementation of core elements of HHAPs varies significantly in the areas of long-term urban planning, real-time surveillance, monitoring and evaluation. Moreover, low levels of inclusion of HHAPs with national policies hinder the overall potential of adaptation measures. The growing impacts of HWs emphasize the urgent need to address spatial heat vulnerability and build urban heat resilience into implementable action plans.