" The cement manufacturers are trying, and have invested millions of dollars in programs like the Sustainable Cement Initiative. They have improved efficiency significantly but are up against the basic chemistry: The chemical reaction that creates cement releases large amounts of CO2 in and of itself. Sixty percent of emissions caused by making cement are from this chemical process alone. The balance is produced from the fuel used in production, which may be mitigated by the use of greener technology. So to "go green," cement makers try to cut the fuel side of the equation."
The industry says "Because of our initiatives, emissions are growing slower than they would without the interventions." But they are still growing like mad. ::International Herald Tribune