Researchers from George Mason University in Virginia, specializing in climate science, have identified regions that may become dangerous or uninhabitable for people in the future due to rising global temperatures. The findings are included in a study published in the Proceedings of the National Academy of Sciences (PNAS), emphasizing the human impact of heat extremes on large populations.
Over the past several years, extreme heat has affected every continent. In the Asian subcontinent, temperatures above 50°C have been recorded with increasing frequency, and in 2022 London saw temperatures exceed 40°C for the first time, a milestone that science had not predicted so soon in climate models.
Current estimates place a practical heat tolerance limit around 31.1°C for outdoor exposure without cooling and without risking serious health effects. If global temperatures continue to rise, the Indus Valley region in India and Pakistan, along with parts of East Asia, the Middle East, and sub-Saharan Africa, could experience conditions that are difficult for the human body to endure.
As an illustration, with a rise of 2°C above pre-industrial levels, the Yemeni city of Hodeidah, home to more than 700,000 residents, could face up to 340 hours of extreme heat per year, equivalent to about 14 days where heat becomes life-threatening for the population at risk. These patterns would intensify heat exposure across others in densely populated areas.
Other hotspots with notable exposure include the Saudi Arabian cities of Dammam and Jeddah, expected to endure roughly 37 and eight days of extreme heat respectively each year. Iran would see Bandar Abbas and Ahvaz facing 29 and three days of severe heat, while Lahore in Pakistan could reach 24 days, and Dubai in the United Arab Emirates around 20 days. In India, Delhi and Kolkata would experience six and five days, respectively.
Excessive heat threatens more than comfort. It elevates the risk of heat stroke and worsens conditions tied to heart and blood pressure, respiratory issues, kidney problems, and other illnesses. The resilience of health systems and the capacity of communities to adapt are put to the test as heat waves become more frequent and intense.
The researchers stress that these results call for proactive preparation, adaptation, and mitigation strategies to protect health, infrastructure, and economies from escalating heat exposure. This includes improving cooling access, urban planning that reduces heat retention, and programs designed to shield vulnerable populations during peak heat periods.
Earlier work has already mapped hot spots of ocean warming, underscoring that climate change touches multiple layers of the planetary system. The current study reinforces a broader narrative about how heat extremes compound risk for societies worldwide and highlights the need for globally coordinated action to curb emissions and support resilience. (Attribution: GMU climate science team, PNAS study.)