Observed heatwave trends have been on the rise in the last four decades according to a research article published in January 2022. The study titled, “Increasing Heat-Stress Inequality In A Warming Climate”, projects further intensification of extreme heat events in the future. Excess heat events like heat waves are an immediate threat to human well-being, as they may contribute to crop failure, worsened wildfires, and heat-related deaths, such as heat exhaustion and heat stroke.
Researchers of the 2022 study claim that societies in the lowest-income regions are projected to have greater difficulties adapting to the challenges posed by a warming climate. Authors claim that their “findings demonstrate continued increases in heatwave exposure inequality because of delays in adaptation capacity in the developing world, compounded by a higher emergence of warming in low-latitude areas where most of the low-income countries occur”.
Research Method and Design
This study used heatwave data from the years 1980-2019 to model future temperatures for 2030-end of the century.
Heatwaves here are defined as “an event during which daily mean temperature exceeded the 97th percentile of local annual mean daily temperature in a reference period for at least three consecutive days”. Authors of the study claim that they are operating under the assumption that vulnerability to heatwave-related risks and degrees of suffering is determined by economic development status.
Researchers split all regions of the world into four socioeconomic classes for income: lowest, lower-middle, upper-middle, and highest, (based on the population weighted per-capita gross domestic product in 2015). They were then able to create a spectrum of economic adaptive capacities. Adaptation capacities include cooling systems, electricity, early detection, and warning systems, and infrastructure.
As reported in the study, a 60% global increase in the total number of heatwave days was recorded over the past 40 years. Average yearly heatwave seasons were 75% longer during the 2010s compared to those in the 1980s. Also, “the maximum decadal amplitude of shock heatwave was between 2.16 (Europe) and 3.27 (North America) °C higher in the 2010s as compared to the 1980s”. Although heatwaves intensified across all socioeconomic classes, the “low-income region” observed the greatest rate of increase in heatwave season length yearly.
In the 2010s, the “high-income region” experienced 30% fewer heatwave days. Sensitivity to heat waves is significantly determined by a society’s adaptation efforts. Regions with relatively low incomes will face greater challenges and vulnerability to heatwaves due to their lack of access to resources that enable adaptation across sectors. Inferior adaptation capacities may hinder or delay institutional heatwaves responses to heatwaves, making societies with lower-scoring GDPs more susceptible to the impacts of rising temperature averages and excess heat.