Here are the world's cities least prepared for extreme heat Some European capitals also appear in the ranking

According to an investigation by the Guardian, this summer saw a rise in mortality associated with heatwaves across Europe: according to the British newspaper's analysis, there were approximately 35,000 more deaths than normally expected – 25,000 of them concentrated in France, Spain, and Germany. The phenomenon could become even more significant and pronounced in the coming decades, partly due to an ageing population and the intensifying effects of climate change.

But just as with territories, not all urban centres face the same level of risk from heatwaves and extreme heat: the effects of high temperatures on the population are determined not only by the actual temperatures reached, however extreme, but also by the level of social vulnerability, demographic characteristics, and the capacity of infrastructure to protect residents in individual areas. A new study from the University of Oxford has analysed these factors for over 200 cities with more than one million inhabitants, producing a global ranking of risk related to extreme heat.

The ranking of cities most exposed to the risks of heatwaves

The University of Oxford research assigned each city examined a score based on several indicators. In addition to temperatures and the frequency of heat exposure, specific demographic and socioeconomic characteristics were taken into account that can increase the likelihood of illness and death linked to high temperatures. These include the age of the population and available economic resources, along with access to cooling systems and the presence of urban vegetation.

From this perspective, India, Pakistan, Nigeria, and Ghana are the countries with the highest number of cities considered most exposed to the consequences of heatwaves. Over 95% of at-risk urban centres are located in South and Southeast Asia or in sub-Saharan Africa. However, the top 50 positions also include major tourist destinations such as Cairo and Bangkok. The Western Hemisphere city with the highest risk score among those analysed is Phoenix, Arizona, which ranks 75th. Further down the ranking, however, appear – in order – Bucharest, Rome, Barcelona, Milan, Paris, and Warsaw, followed by Madrid, Munich, and Berlin.

A comparison between different major cities shows that greater exposure to high temperatures does not necessarily imply a higher overall risk: for example, Kuala Lumpur – in Malaysia, another rising tourist destination – presents rather concerning levels of exposure to extreme heat, yet at the same time the University of Oxford study suggests it appears to benefit from a greater capacity for adaptation (at least on a statistical basis), linked in part to the presence of vegetation across its territory – which limits the "heat island" effect – and to a degree of energy self-sufficiency.

Can we adapt to extreme heat?

According to other recent estimates, in recent years extreme heat has caused an average of over 540,000 deaths per year worldwide, of which 175,000 in Europe. And with the increasing frequency and scale of violent climate events, the ability of individual cultures and societies to adapt to higher temperatures has become a subject of growing scientific interest. Throughout history, various populations have developed behaviours, technologies, and specific forms of organisation to cope with the extreme environmental conditions in which they lived.

One example is the passive cooling of buildings, based on design features that promote natural ventilation and insulation from the external environment, reducing the need to use air conditioning systems. Techniques of this kind have been adopted by numerous peoples, and demonstrate how architecture can contribute to adaptation to climatic conditions without necessarily entailing an increase in energy consumption.

Adaptation, however, concerns not only buildings but also habits and the organisation of daily life. In 2023, for example, during a particularly hot summer, then German Health Minister Karl Lauterbach suggested taking inspiration from Spain and introducing a longer lunch break, along the lines of the siesta – according to Lauterbach, adjusting working hours could have made a real difference for professions most exposed to high temperatures.