Cities are tackling rising heat – but they have to avoid a dangerous trap.Guardian Chris Michael Thu 15 Aug 2024 Beneath the streets of Seville – the city nicknamed “El Sartén”, the frying pan of Europe, where summer temperatures regularly top 40C – a €5m (about £4m ) cooling strategy is taking the city back in time. The millennium-old Persian technique of “qanat” features underground channels filled with water and shafts that bring the cooler underground air to the surface. Seville is doing the same, adapting a 1992 experimental qanat to use renewable power and – in a new twist – pumping the water to the tops of buildings, where it will trickle down inside the walls to cool them. Even the benches will be chilled. It sounds like a luxury, but it is nothing of the sort. Heat has become a leading health threat to cities, and not just in Seville. Last year645 people diedfrom overheating in Phoenix. Counterintuitively, the fire trucks in Phoenix now carry ice, packed into body bags. Its first responders have learned through the experiences of the past few years that you can save lives by packing overheated people into ice – a cold-water immersion therapy used in extreme endurance tests, such as military training and marathon running – in order to bring their temperature down rapidly while whisking them to hospital. Nor is Phoenix an outlier. On this year’s hajj, the Muslim pilgrimage to Mecca, an estimated 1,300 people died in heat that surpassed 51C – more than half way to water’s boiling point, a toxic level that cooks human cells, thickens blood and cuts off oxygen to the brain. Extreme heat in New Delhi has killed more than 100 people in the last three months alone, probably a vast undercount. It is now considered unsafe to work outside at all in Doha, a factor behind the deaths of an estimated 6,500 migrant workers in the 10 years after Qatar won the right to host the World Cup.
Some cities now offer cooling centres, where you can escape the heat, though most people do not want to use them on a regular basis. There are policy changes that can help: laws protecting workers, heatwave response plans, and spatial mapping that can identify the hottest parts of a city. Cities are not just where the rapid heating of our planet is highest, owing to the concentrating effect of concrete and asphalt and the relative lack of natural cooling factors such as lakes, soil or shade. They are also where our increasingly urban species will have to face it. So the architects, planners and politicians who serve those cities are seeking ways to either reduce or mitigate that heat, such as the qanat cool water beneath the streets of Seville.An increasing number of cities are experimenting with green roofs, covered in plant life, or “white roofs” like those in New Delhi, where exposed concrete is whitewashed. And the architects are letting their imaginations run Much is made of tree-planting, such as Singapore’s effort to seed more than 7m new trees, and of green space in general: parks and gardens can, and do, offer a huge amount of relief. Seville and other cities are installing awnings along streets for shade; LA is one of a number of places experimenting with “cool pavements”, employing a type of paint that can reduce heat up to 11C.
An increasing number of cities are experimenting with green roofs, covered in plant life, or “white roofs” like those in New Delhi, where exposed concrete is whitewashed. And the architects are letting their imaginations run wild; in Abu Dhabi, for example, Arup has designed a tower that has computer-controlled folding screens that open and close like flowers, based on the sun’s position.wild; in Abu Dhabi, for example, Arup has designed a tower that has computer-controlled folding screens that open and close like flowers, based on the sun’s position......read on https://www.theguardian.