About 90% of the population is expected to live in urban areas by 2050. However, the lack of shade and poor building design magnify temperatures, with increasing health risk. Professor Prashant Kumar, an urban heat researcher at the University of Surrey, said: “The built environment, with all its concrete and gray infrastructure, traps heat and that heat can stay for longer, well into the night.” It is called the urban heat island, with the centers of major cities such as London and Manchester up to 10 degrees Celsius warmer than surrounding rural areas. Live UK weather updates – ‘major incident’ as alert level 4 declared But figures given to Sky News show a significant temperature gradient even in a relatively small town like Guildford in Surrey. Professor Kumar’s team has a network of sensors across the region. They show that by early Monday afternoon of this week (11 July) the temperature in a residential area had risen to 35 C (95 F). That’s 7 degrees Celsius warmer than a nearby forest and 6.5 degrees Celsius warmer than a park. The residential area also took longer to cool down. Even at midnight it was almost 22 C (71.5) F – about 3 C warmer than the park or forest. “This shows that we should not just focus on cities,” said Professor Kumar. “We should also look at these smaller cities, where there is a need to make them more resilient to urban heat.” Image: Partly tanned rowers enjoy the weather on the River Thames near Hammersmith in London. Photo: Associated Press Read more: National emergency as extreme heat red alert issued for first time across England Revealed – areas of England most vulnerable to warmer weather From blankets on glaciers to ice creams forever, Europe is finding new ways to cope blistering heat Many urban areas were built long before climate change began to accelerate. Mossbourne Parkside Academy in East London dates back to 1898. Large windows with inadequate ventilation can make it difficult to keep classrooms cool. However, staff use blackout blinds to keep out the sun and interior doors are left open to encourage drafts. Children take regular breaks in the shade outside and drink plenty of water. Laura Green, the headteacher, said: “The building is not built for the conditions we are experiencing at the moment. “It’s something we have to look at in the future. “It’s not just schools, it’s other buildings – how do we adapt our infrastructure to withstand these conditions.” Intense thermal images Image: Thermal image showing a road, with houses and road radiating heat In a thermal camera it is clear to see the heat emitted by hard surfaces such as brick, steel, concrete and asphalt. In contrast, natural areas are much cooler, but not only because of the shade cast by the trees. Leaves use some of the sun’s energy to evaporate water, keeping them – and the surrounding air – cooler. It is natural air conditioning. Image: Many urban areas were built long before climate change began to accelerate. David Elliott runs a charity called Trees for Cities that plants shade for the future. “We want to see hundreds of thousands more trees in our cities and on our streets. There is so much to do,” he said. “There has never been more focus and funding for trees in general, which is great. “But much of that funding has been focused on the countryside. “We need to change that balance to invest a lot more in our cities and have a lot more trees and green spaces in our cities.” ‘Hair raising’ The government has said it wants 150,000 new trees in urban areas. But the funds for this year’s planting have already been used up. Plane trees were widely planted in affluent boroughs and central London in the 18th century, mainly for aesthetic reasons. But degraded areas are more exposed to the full intensity of the sun. “There is a frightening correlation between parts of our cities that have less green space with fewer trees and the lowest income levels,” Mr Elliott said. “This association is well known across the UK and around the world, so we really want to focus our efforts on these hotspots.” An average of 2,000 people a year die today as a result of the heat. But by 2050 this is expected to rise to 7,000 per year. Prof Kumar said: “Everyone is affected by heat in one way or another. “If you’re young and fit, you won’t feel comfortable. “But if you’re elderly or have any pre-existing conditions, you’re at a higher risk of heatstroke or cardiovascular or respiratory effects. And that can be fatal.”
