Concrete, Flyash, and the Environment - Proceedings
A forum held 8 December 1998 - Sponsored by EHDD Architecture and Pacific Energy Center
CO2 Emissions From Cement Production
Malhotra, V.M., Role of Supplementary Cementing Materials in Reducing Greenhouse Gas Emissions, submitted for publication in American Concrete Institute Concrete International, 1998. Dr. Malhotra writes "worldwide production of cement accounts for almost 7% of the total world CO2 production" based on the following figures: 1995 cement production at 1.4 billion tons, CO2 emissions at 1 ton per ton of cement; and 1995 global CO2 emissions at 21.6 billion tons.
Wilson, Alex,, in Environmental Building News, Volume 2, Number 2, March/April 1993. Wilson states "Worldwide, cement production now accounts for more than 1.6 billion tons of CO2-over 8% of total CO2 emissions from all human activities." This was based on the following figures: cement production at 1.25 billion tons, CO2 emissions at 1.25 tons per ton of cement, and global CO2 emissions of 20 billion tons.
Mehta, P.K., Role of Pozzolanic & Cementitious By-Products in Sustainable Development of the Concrete Industry in Sixth CANMET/ACI/JCI Conference: Fly Ash, Silica Fume, Slag & Natural Pozzolans in Concrete, 1998. Dr. Mehta cites global cement clinker production (portland cement is made from 95% clinker) as responsible for 7-8% of CO2 emissions.
Dan Lashof at NRDC in Washington DC cites 1995 Intergovernmental Panel on Climate Change (IPCC), Working Group II, p. 661. (This is the official UN technical document used for the global climate change negotiations that are going in at Kyoto, Argentina, etc.):
0.75 tons of CO2 per ton of cement from energy use + 0.50 tons of CO2 per ton of cement from calcining limestone _____________________________________________________________ = 1.25 tons of CO2 per ton of cement total x 1.25 billion tons of cement produced in 1991 (1996 = 1.48 Bt) _____________________________________________________________ = 1.56 billion tons of CO2 annually divided by 22 billion tons of Global CO2 emissions in 1991 _____________________________________________________________ = 7% of global CO2 emissions.
U.S. cement production and CO2 emission are smaller both in total quantity and as a percentages since the U.S. construction industry uses a wider diversity of construction materials. Numerous other countries do, however, look to the U.S. and Europe to adopt our material technologies and standards.