A recent article in PLOS Climate calls for the development of a global early warning system for extreme heat. The paper notes that one of the chief barriers to developing such a system is that there is not currently an agreed upon definition of extreme heat. Such a definition is difficult to agree upon because vulnerability to extreme heat varies widely according to many different risk factors.
The paper identifies several state-of-the-art heat warning systems, including a Portugese system that has existed since 1999. The authors also note that effective warning systems must link warnings with heat-health planning efforts and points to the UK's system as an interesting example of this coordination. The French system provides a good example of effective communication of the warning and the article points to Australia, Senegal, and the U.S. as providing good models of the development of heat metrics.
Reference
Brimicombe C, Runkle JD, Tuholske C, Domeisen DIV, Gao C, Toftum J, et al. (2024) Preventing heat-related deaths: The urgent need for a global early warning system for heat. PLOS Clim 3(7): e0000437. https://doi.org/10.1371/journal.pclm.0000437