Madrid’s urban centre has the most extreme urban heat island (UHI) “hot spot” of six major cities around the world, with temperatures 8.5 degrees Celsius hotter than rural surroundings, according to a new international survey by the consulting firm Arup. Arup’s Urban Heat Snapshot analysed the temperature in the urban centres of Cairo, London, Los Angeles, Madrid, Mumbai and New York. Mumbai had the second most severe hot spot (7 degrees Celsius), while New York and London both had hot spots of 4.5 degrees Celsius.
Arup used AI and satellite images to map the hot spots. It then used its digital analytics tool UHeat to understand the difference in air temperatures experienced from neighbourhood to neighbourhood on the hottest day in each city in 2022, explains Arup in a statement. In the majority of cities, the hottest spots had less than 6 per cent vegetation cover, while the coolest locations had over 70 per cent. Three of the cities studied experienced their worst UHI hot spots during the evening or night-time.
The number of cities exposed to temperatures of 35 degrees Celsius and above is expected to triple by 2050, according to Arup. The survey is designed to help cities understand how heat is impacting them and what can be done to reduce temperatures, writes Arup. The authors recommend that cities focus on increasing tree canopy cover; creating more permeable surfaces such as bare or planted soil; greening facades and roofs; establishing cool islands with shelter and water provision; and adjusting behaviour change, such as closing shops during peak heat.
Designers must think creatively to “strategically and equitably deploy nature throughout our cities”, according to Dima Zogheib, Nature Positive Design Lead at Arup. “We’ve inadvertently designed many of our cities to be hot. We’ve pushed out nature – concreted our streets, built high in steel and glass. Today we have the advanced digital tools to help us rapidly pinpoint where investment in solutions can make the greatest impact,” he said in the statement. ce/em
