According to Maroun Rahme, founder of Nu-Rock, which makes building products out of waste materials such as coal ash and steel slags, just by implementing this technology “and doing nothing else” Australia could achieve its net-zero target by 2030.

“The cement industry [alone] produces 25 per cent of the world’s CO₂ emissions. They say 8-9 per cent, but they don’t include the limestone that they burn that releases CO₂ as well,” says Rahme.