Climate change is going just as badly for cities as we have been warned it would. Extreme weather is increasingly common and severe globally. Australian cities have endured a number of recent disastrous events.
Itâll get worse, too. The Intergovernmental Panel on Climate Change factsheet outlining impacts on human settlements is a very sobering read. It also pithily sums up the situation cities face:
Implicit in this wording is a hopeful truth: adapting to climate change is a daunting task, but the âhowâ is not a mystery. The opportunity is right in front of us, in our streets, buildings and parklands. Around the world we are seeing effective retrofitting of cities to adapt to more extreme weather.
Here are a few inspiring examples.
Keeping cities cool
Planting trees to create shade is an obvious response to hot weather. However, in many cities itâs still a struggle just to stop the losses of trees. Future hot, dry climates will add to the challenge of urban greening.
Medellin in Colombia is one city making inspiring progress on this front. With an urban greening budget of $16.3 million, it has created a network of 30 âgreen corridorsâ through the city. These have reduced urban heat island effects by 2 degrees Celsius three years into the programme. As these densely vegetated corridors mature, they are expected to eventually deliver 4 degrees Celsius-5 degrees Celsius of cooling.
Vienna, Austria, has had an urban heat island strategy in place since 2018. It includes planting 4,500 trees each year and subsidies for street-facing green walls.
The city has developed a series of âcool streetsâ â traffic-calmed spaces with light-coloured road surfaces, âfog showersâ that activate on hot days, water features, shade trees and drinking fountains. Eighteen cool streets were delivered as pop-ups, with another four in place permanently to provide refuges on hot days. Vienna also has an extensive network of public swimming pools where residents can cool off.
Limiting flood damage
Urban green space can also be valuable for intercepting and absorbing stormwater to prevent flooding.
A spectacular example is Bishan-Ang Mo Kio Park in Singapore. It was the site of a concrete drainage canal that was transformed into a 3.2 km winding stream in 2012.
The 62-hectare park along the gently sloping banks of the stream serves a densely developed residential area. In wet conditions, the stream swells up to 100 metres wide. As stormwater gently flows downstream, it drains away into the landscape.
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