As with city hall and true love, you can’t fight chemistry. And that’s bad news for the cement business.
Cement—the ubiquitous binding agent that makes possible the concrete buildings, roads, sidewalks, sanitary sewers and all the rest of the grey, unseen infrastructure that forms the foundation of modern life—is produced by heating limestone and other materials to 1,450° C in a massive rotating kiln, at which point limestone breaks down into its constituent components of lime and carbon dioxide. The lime goes on to form cement powder; the carbon dioxide—38 per cent of limestone by weight—goes up the stack. Burning coal or petroleum by-products to generate the extreme heat necessary for this chemical reaction creates even more greenhouse gases.
For every tonne of cement produced, more than three-quarters of a tonne of carbon is released into the atmosphere. The industry accounts for more than eight per cent of global carbon emissions. This inescapable chemistry of cement and rising government action on climate change have conspired to push the industry into an existential crisis. It has also spurred the renaissance of a building material that concrete replaced more than a century ago.