Concrete was the villain. Now it might be the answer, if we ask harder questions

When I was going through architecture school, concrete was taught as one of the worst materials environmentally, the embodied energy villain of the construction industry. The numbers backed it up then and still do. Cement manufacture is responsible for roughly 8 per cent of global CO2 emissions, and if the cement industry were a country it would be the third or fourth largest emitter on earth [1].