five percent production 5 percent of global CO2 emissions four-and-a-half billion tons by 2050 also emits carbon 5 percent of global CO2 emissions Concrete is the second most consumed substance on Earth making cement making cement ordinary cement production making cement ordinary cement production 5 percent of global CO2 emissions ordinary cement production ordinary cement production 5% of all man-made carbon emissions. 5 per cent of global CO2 emissions Concrete is the second most consumed substance on Earth making cement making cement making cement production of cement 5 percent of global CO2 emissions making cement 5 percent of global CO2 emissions