1. Cement, the most widely used construction material in the world, is a major source of CO2 emissions.
As a key input into concrete, every year over four billion tonnes of cement is produced, contributing to around eight per cent of global CO2 emissions. With global cement production projected to increase to over five billion tonnes by 2050, cement is expected to play a key role in the expansion of the built environment particularly in developing countries. This potential increase comes at a point when, according to a number of scenarios, cement sector emissions need to fall — fast.