As a growing number of people realise, climate change isn’t just about large-scale, somewhat slow change; it’s also about more frequent and more extreme “weather events,” like “hundred-year storms” happening two or three times in 15 years, for example.
When those events happen, cities, especially those built on the side of rivers, tend to be struck and are rarely built for those kinds of extremes—many have also been expanding into wetlands and floodplains, which does not help their case—which is why officials around the world are implementing techniques to absorb or divert water and protect urban areas from the effects of climate change.
There are various solutions, often regrouped under the term “sponge,” as in turning cities into sponges. “Imagine a city made of sponges, or sponge-like surfaces, able to soak up rainwater, overflowing rivers or ocean storm surges and release stored water during droughts.”
And wouldn’t you know it, rediscovering how nature does things provides many solutions and makes for better places to live.
[A]round the world officials are moving away from the traditional, hard infrastructure of flood barriers, concrete walls, culverts and sewer systems, and toward solutions that mimic nature. They are building green roofs and parks; restoring wetlands, swales and rivers; digging storage ponds; and more. Such projects — called by various names, including sponge cities, porous cities or blue-green infrastructure — also improve city dwellers’ quality of life. […]
Mr. Yu [Kongjian, a landscape architect at Peking University] said that the sponge development philosophy was not a new concept, but rather a way to live in cities that used their natural features, considered their climate and applied locally appropriate solutions.
Instead of getting rid of the water as quickly as possible, the goal is to make cities more porous, so they slow down water and absorb more of it, which has the added benefit of reducing runoff water, a significant source of pollution in urban waterways.
China is already working hard to update hundreds of cities, and some of the numbers are incredible.
[T]he Yangtze River Beach Park [in Wuhan]. Where embankments once lined the river, the project added gentle slopes of vegetation and permeable surfaces for more than four miles; 45,000 trees, 125 square miles of shrubbery and 150 square miles of grass; 15 soccer fields; and seven swimming pools. The park now sequesters 725 tons of carbon dioxide a year, reduces temperatures by more than 5 degrees Fahrenheit compared with the rest of the city and has more than doubled the value of the land, according to a study.
The article linked above also shares examples in New York and Philadelphia in the US and Malmö in Sweden. But it’s a global issue. As with much of climate change and economic issues, the global south stands to be hit hardest while controlling the fewest resources—another reason to make the climate transition greener and fairer.
Image: Heavy rains along the Yangtze River in Wuhan in 2020 caused flooding. A new sponge project to absorb rainwater along the riverbank is adding gentle slopes of vegetation and permeable surfaces; 45,000 trees, 125 square miles of shrubbery and 150 square miles of grass; 15 soccer fields; and seven swimming pools. Getty Images.