2018/08/24: concrete is an invention as transformative as fire or electricity. Since it came into widespread use around the turn of the 20th century, this man-made stone has changed where and how billions of people live, work and move around. It is the skeleton of almost every apartment block and shopping mall, and of most of the roads connecting them. It gives us the power to dam enormous rivers, erect buildings of Olympian height and travel the world with an ease that would astonish our ancestors.
The number of urban dwellers is rising by about 65 million people annually, according to the United Nations Population Division. That’s the equivalent of adding eight New Yorks - or 22 Torontos - to the planet every single year.
There’s no way cities could grow this fast without concrete.
Making all that concrete, however, takes a heavy toll on the atmosphere. The cement industry produces 5 per cent to 10 per cent of total carbon-dioxide emissions worldwide, putting it behind only coal-fuelled power plants and automobiles as a source of global-warming gases.
The most frightening aspect of our dependence on concrete might be that the structures we build with it won’t last. The vast majority of them will need to be replaced - and relatively soon.
To make matters worse, we’re running out of one of concrete’s essential ingredients: sand. Mining sand is its own colossal industry with its own litany of environmental devastations.
It’s time to start thinking about how much concrete we can afford.