Metropolis meltdown: the urgent steps we need to take to cool our sweltering cities
https://www.theguardian.com/artanddesign/2022/jul/14/climate-crisis-metropolis-meltdown-urgent-steps-cool-sweltering-cities
Excerpt: ...As hot, developing nations become more prosperous, and prosperous nations become hotter, the International Energy Agency estimates that the energy spent on air conditioning will triple by 2050 – a growth equivalent to the current electricity demand in the US and Germany combined. ...The biggest cause of the urban heat island effect – which can make cities up to 10C warmer than neighbouring rural areas – is the stuff they are made of: hard, dark, dense materials like concrete, brick, tarmac and asphalt, which absorb the sun’s heat during the day, and re-radiate it at night. It sounds too simple a solution, but some argue that one of the most effective measures to cool cities down is to make their surfaces reflect light, rather than absorb it – particularly where you might not think to look: up on the roof. Researchers at the University of Oxford found that making the rooftops of buildings a lighter, more reflective colour could reduce daytime temperatures by up to 3C during a heatwave. That might not sound like a huge difference, but the scientists concluded that such a drop could reduce the number of heat-related deaths by up to a quarter – a massive life-saving measure, given there were over 2,500 excess deaths from heat during the 2020 heatwave. ...Research by Nasa has shown that a white roof in New York City can be 23C cooler than a typical black asphalt roof on the hottest day of the summer. The city’s Cool Roofscampaign, which was launched in 2009, has already seen over 900,000 sq metres of roof space covered in a white reflective coating, saving almost 4,000 tonnes of CO2 a year from cooling emissions. ...most urbanists agree that planting trees is one of the best ways to cool cities down – without the danger of reflecting sunlight where it isn’t wanted.…