John Vidal writes:

Cement, the key component of concrete and one of the most widely used manmade materials, is now the cornerstone of global construction. It has shaped the modern environment, but its production has a massive footprint that neither the industry nor governments have been willing to address.

Because of the heat needed to decompose rock and the natural chemical processes involved in making cement, every tonne made releases one tonne of C02, the main greenhouse warming gas.

Including the new Crossrail line through London, the building of Britain’s four largest current construction projects will, if completed, together emit more than 10m tonnes of CO2 – roughly the same amount as a city the size of Birmingham, or what 19 million Malawians emit in a year.

Nearly 6% of all UK greenhouse gas emissions, and up to 8% of the world’s, are now sourced from cement production. If it were a country, the cement industry would be the third largest in the world, its emissions behind only China and the US.

So great is its carbon footprint that unless it is transformed and made to adopt cleaner practices, the industry could, on its own, jeopardise the whole 2015 Paris agreement which aims to hold worldwide temperatures to a 2C increase. To bring it into line, the UN says its annual emissions need to fall about 16% in the next 10 years, and by far more in the future. [Continue reading…]