This is explained by Lorenzo Chelleri, director of the JURECA Research Institute (Just and Resilient Carbon Neutral Places) and director of the Master’s Degree in Urban Resilience and Sustainable Transitions at UIC Barcelona, whose research focuses on adapting cities to the challenges arising from climate change and on developing more resilient and sustainable urban models.

According to the researcher, many cities become “heat traps” during periods of extreme temperatures. Excess asphalt and concrete, street orientation, building height, and even the colour of façades contribute to the so-called “urban heat island” effect and make it harder for cities to cool once the sun sets. “The problem is not only the daytime temperature peaks but also the fact that many cities do not cool down at night,” explains Chelleri.

Streets and façades absorb heat during the day, store it and release it slowly throughout the night. This prevents temperatures from falling and can ultimately become a public health issue that goes beyond the immediate risk of heatstroke, as the body needs a few hours of cooler conditions to recover from the heat accumulated during the day.

Cities can also be part of the solution

In response to this situation, the researcher advocates moving towards a model of “climate-conscious urban planning”, which incorporates heat adaptation criteria into city planning. Improved water management, the use of materials that reflect solar radiation, and the design of streets and buildings that enhance ventilation are some of the strategies that, according to the expert, can help reduce the impact of high temperatures.

“It is not enough to open cooling shelters or plant more trees; we must change the way we construct and refurbish our buildings,” states Chelleri. He emphasises that cities are not condemned to become furnaces during the summer and that we already have the knowledge and tools required to design urban environments that are more resilient to heatwaves.

The JURECA Research Institute at UIC Barcelona promotes multidisciplinary research aimed at addressing the challenges of climate change and the relationship between people and their environment, with the goal of generating knowledge and solutions that contribute to the development of fairer, more sustainable cities adapted to future climate conditions.