Spatiotemporal changes in Universal Thermal Climate Index in the Middle East and North Africa

Abstract

A fast temperature rise has made the Middle East and North Africa (MENA) region a global hotspot of extreme heat events. Previous studies conducted in the region to evaluate extreme heat based on temperature were inadequate for assessing heat based on human thermal impacts. The present study employed the Universal Thermal Climate Index (UTCI). This index evaluates the changes in heat related to human thermal stress in MENA. This analysis employed the ERA5-HEAT dataset, derived from the Copernicus climate change service portal. The results showed that all the regions experienced an average daily UTCI representing extreme heat stress for 1 to 25 days. The daily maximum UTCI goes to the extreme level on average of 1 to 175 days a year, with the highest in the east and southwest. The annual mean UTCI in MENA is increasing from 0.1 to 0.7 °C/decade, with the highest increase in the northeast, covering eastern Saudi Arabia and most parts of Iraq and Syria. This caused a decrease in cold stress and an increase in hot stress days, with the highest increase in strong thermal stress days in the range of 4 to 16 days/decade in most of MENA. The trend in daily maximum UTCI also showed an increase in the range of 0.1 to 0.6 °C/decade, which caused an increase in the number of daily maximum UTIC above 46 °C or extreme level by 1 to 16 days/per decade, with the highest increase in central Saudi Arabia, northern Sudan and southern Mauritania. This study is the first to investigate UTCI trends in the MENA region and is expected to provide valuable information on hotspots and temporal trends in UTCI, serving as a foundation for future heat action plans to prevent heat-related illnesses throughout the region.