Monitoring Temperature Extremes, a Framework for Global Early Warning Systems

Temperature extremes are a deadly natural hazard and heavily affect socio-economic and natural systems. Several metrics have been developed to characterize the risk of temperature extremes to human health. At the national or subnational level, ad-hoc indicators are commonly implemented by civil protection authorities, meteorological services and other entities, and are often used to issue warnings and define reactive measures during emergencies. International standards dedicated to monitoring and anticipatory action, as well as for aggregating data for retrospective analysis or research, are not available. Similarly, models for the temperature-mortality risk are available only in some countries, mostly high-income ones, but not elsewhere.

With ERA5 as data source (ECMWF atmospheric reanalysis of the global climate covering the period from January 1940 to present), we use a combination of temperature anomalies and feels-like temperature indicator (Universal Thermal Climate Index - UTCI) to define events of relevance, particularly for the humanitarian community and the civil protection community. Population and urbanisation data are employed to pinpoint locations with significant potential impacts, thus informative for preparedness and response analysis. The prospective use of discrete events as defining entity, together with vulnerability and exposure mapping, facilitates the tracking of the events and the identification of more specific areas of interest, thus helping to characterize impact before, during and after extreme temperature events.

We assess and validate the analysis based on a dataset of past impactful events, and propose a synthetic classification to highlight the level of awareness needed for the humanitarian community, in line with the impact severity. The resulting product is suitable for monitoring temperature extremes at global level in multi-hazard early warning systems, like the Global Disaster Awareness and Coordination System (GDACS).