The world’s coastlines are turning to concrete, at a huge cost to wildlife and the climate. But new technologies may offer a way to shore up coasts while benefiting biodiversity.
It’s one of the most impressive feats in modern engineering, and crossing the world’s longest sea bridge – the 55km (34 miles) Hong Kong-Zhuhai-Macau bridge, which opened in October 2018 at a cost of $20bn (£15.9bn) – certainly has its benefits. But impressive as it appears, this mammoth construction project, like so many others, has come at a cost.
No less than one million tonnes of concrete were used in the eight years it took to build the bridge. It was this concrete that invaded the habitat of the critically endangered pink dolphin, and is thought to be the reason that dead dolphins washed up on nearby shores while the population near the bridge plummeted by 60%. Of course, dolphins weren’t the only victims – habitats are destroyed and countless other marine species are affected when large amounts of concrete are poured into the ocean.
Destruction of this kind is often the cost of using concrete – the most widely used manmade material on Earth. With three tonnes per year used for every person in the world, there are few parts of the planet that concrete hasn’t reached. The production of concrete is also a huge emitter of CO2. At least 8% of humanity’s carbon footprint comes from the concrete industry, mostly from the production of cement – one of concrete’s principal components. The cement industry generates around 2.8 billion tonnes of CO2 per year – more than any country other than China or the US.