A groundbreaking study from Oxford University underscores a staggering reality: more than 95 per cent of the cities facing the highest risk from extreme heat are located in South Asia, Southeast Asia, and Sub-Saharan Africa. This alarming research, which evaluates the heat vulnerability of urban areas, identifies Al Basrah in Iraq as the most at-risk city, highlighting a critical intersection of soaring temperatures, poverty, and insufficient resources for adaptation.
Cities Under Siege
The research assesses 205 urban centres with populations exceeding one million, taking into account not only temperature extremes but also the socio-economic vulnerabilities of their residents and the capacity of cities to cope with heat stress. The study, published in the journal *Sustainable Cities and Society*, reveals that countries such as India, Pakistan, Nigeria, and Ghana are home to the majority of cities with elevated risk scores.
Notable urban destinations like Cairo, Bangkok, Hanoi, and Jaipur feature prominently in the top 50 most threatened cities, raising concerns about the implications for tourism and commerce in these critical regions.
The Complex Nature of Heat Risk
Lead author Nethmi Jayaratne Kariyawasam emphasised the need for a multifaceted understanding of urban heat risk. “Our study highlights that risk is not solely dictated by exposure to high temperatures,” she stated. “It is imperative to consider the various pathways through which heat risk manifests.”
In many major cities across Asia and Africa, extreme heat aligns with high vulnerability and limited coping mechanisms. This combination creates a perilous environment, significantly increasing the risk of heat-related health issues, and in some cases, life-threatening conditions.
Measuring Heat Exposure and Vulnerability
The research employs a metric known as cooling degree days to measure heat exposure, taking into account factors such as air temperature, humidity, and wind. Vulnerability is assessed through demographics, including the proportion of young children and elderly residents, as well as economic indicators and access to cooling technologies. Coping capacity is evaluated based on urban green spaces, tree cover, and the affordability of electricity.
Surprisingly, some of the hottest cities, including Bangkok and Kuala Lumpur, rank lower on the risk scale due to their urban greening initiatives and more affordable energy options. Conversely, cities like Karachi and Faisalabad in Pakistan, along with Kaduna in Nigeria, face severe risks despite moderate temperatures, largely due to poverty, limited vegetation, and inadequate access to cooling resources.
A Global Perspective on Heatwaves
The findings arrive amid a severe heatwave enveloping Europe and the UK, where France reported nearly 2,000 excess deaths during a record-breaking June heatwave. Experts warn of further extreme temperatures in the coming days, underscoring the urgent need for effective heat risk planning. “Our research indicates that heat risk strategies must explicitly address not only exposure to high temperatures but also the underlying vulnerabilities and coping capacities,” said Dr Radhika Khosla, co-supervisor of the study.
As the demand for air conditioning surges globally, many communities find themselves unable to afford this energy-intensive form of cooling. Dr Khosla cautioned against an over-reliance on air conditioning, which could exacerbate global warming in a destructive cycle. “We must adopt a nuanced approach to ensure safety and comfort for all, prioritising passive cooling and low-energy technologies as initial solutions,” she advised.
Dr Jesus Lizana, another co-supervisor of the study, noted that this research provides a first-of-its-kind globally harmonised assessment of urban heat risk, serving as a crucial tool for identifying regions that require urgent adaptation efforts.
The study also highlights that while city-wide scores can provide a general understanding, they may obscure stark inequalities within urban populations, particularly affecting residents of informal settlements and low-income households who face significantly greater risks.
Why it Matters
The implications of this research are profound. As climate change continues to intensify, the cities most at risk are often those least equipped to deal with its impacts. Understanding urban heat risk is imperative for developing targeted interventions that protect vulnerable populations. This study not only raises awareness of the urgent challenges posed by extreme heat but also serves as a call to action for policymakers, urban planners, and communities worldwide to implement adaptive strategies that foster resilience in the face of an increasingly hostile climate.