by John Vidal, The Guardian
Tucked away in volume three of the technical data for Britain’s £53bn high speed rail project is a table that shows 20m tonnes of concrete will have to be poured to build the requisite 105 miles of track, culverts, bridges and tunnels. It is enough, it has been calculated, to pave over the entire city of Manchester.
A more modest 3 million tonnes of concrete will be needed to construct the Hinckley B nuclear power station in Somerset, and the proposed new runway at Heathrow will require one million tonnes.
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.