Cement

The world consumes over four billion tons of cement each year, making it second only to water as the most heavily consumed substance on Earth. Cement production creates roughly 8% of global carbon dioxide emissions because it involves burning lots of fossil fuels to create the necessary heat to form it as well as because heating the limestone in it releases greenhouse gases.

Concrete is the most abundant manufactured material in the world. It is primarily composed of water, cement, and aggregate (sand and gravel.) Cement manufacturing is responsible for about 8% of the world’s total CO2 emissions, primarily a result of the chemical reaction of heating limestone and the combustion of fossil fuels used to provide the heat.