Even as policymakers seek to implement early warning systems to help people prepare for extreme heat events, those most vulnerable to heat stress are being overlooked, experts say.
Outdoor workers who face the highest exposure to heat, plus infants, the elderly, and those with medical conditions who may have a reduced ability to regulate their body temperature, are more vulnerable to heat stress than others. For these groups and their caregivers, timely warnings that allow them to take protective action are essential—and this is where heat thresholds play a crucial role, write climate scientist Chloe Brimicombe from the Wegener Center for Climate and Global Change in Austria, and researchers Clara Heil and Jakob Eggeling from the Aerosol and Climate Lab in Sweden, in a guest post for Carbon Brief.
But they say a lack of data is holding back efforts to establish adequate thresholds, a lag that is running up against a United Nations target to have early warning systems for all by 2027.
On assessing 931 peer-reviewed studies that use the standard wet-bulb globe temperature metric to explore heat stress thresholds for various demographics, the team found a pervasive gender and age bias that left pregnant women, recent mothers, children, and the elderly underrepresented. Of the studies, 257 explored gender-based heat stress differences, while 154 focused on men. The authors say this emphasis partly owes to men being over-represented in jobs where heat exposure is an occupational risk.
Only three of the 257 papers studied pregnant women, despite a growing body of knowledge that they are particularly vulnerable to heat.
Only five papers considered children aged one to five, just one focused on newborns, and none focused on babies under a year old.
Only four papers consider how heat stress affects people aged 65 years and older, and none of them exclusively studied elderly women.
“When assessing the reception and response to extreme heat warnings, the perceived threat of danger is the strongest factor in why people do or do not heed them,” write Brimicombe and her team. “This means it is even more important to fully understand which groups are most at risk.”
“By tailoring early warning systems to individuals needs and requirements, effective warnings can promote societal resilience by protecting the most exposed and vulnerable,” they add. “Targeted heat thresholds are fundamental to this.”
