Finding the right thresholds to trigger action in Heat Wave Early Warning Systems in Spain

In Spain, the State Meteorological Agency (AEMET) has been successful in using weather prediction models to forecast short- and medium-range extreme temperatures, and an early warning system (Meteolerta) has been implemented in cooperation with European EUMETNET member countries (MeteoAlarm).

Enhanced extreme temperature forecasts for future climate-change scenarios have significant human health implications, including increased mortality and morbidity, thus indicating a clear need to mitigate these effects and adapt to climate change. In this regard, Spain’s Ministry of Health, Social Services and Equality implemented a National Plan for Preventive Actions against the Health Effects of Excess Temperatures as long ago as 2004, from June to September annually, which is activated when the AEMET’s forecasts indicate that a given threshold temperature will be exceeded.

The determination of such a heat-related mortality trigger temperature is a key element, not only when it comes to impact on mortality but also for the implementation of prevention plans. In addition, the current trend in the population pyramid, namely an expansion in the over-65 age group – a cohort that is particularly vulnerable to extreme thermal events – means that this temperature must be re-designated on the basis of new climate and mortality data.