For years the conventional wisdom has been that greenhouse gas emissions from production of portland cement were about 5% of total greenhouse gas (GHG) emissions. A review of the 2015 data generated by the EPA's Greenhouse Gas Reporting Program (GHGRP), however, tells a different story.
All large emitting facilities in the U.S. are required to report their emissions each year. In 2015, there were 8,003 facilities in nine industries that reported with direct emissions totaling 3.05 billion CO2 equivalent metric tons. An equivalent metric ton means that other greenhouse gases are converted into an equivalent amount of CO2.
According to EPA estimates, that 3.05 billion metric tons is about half of the total U.S. greenhouse gas emissions. Small point sources like automobiles, homes, and small industrial facilities are not required to report.
Cement production is always at "large emitting facilities." There were 95 reports from cement production facilities in 2015, which represents nearly every cement plant in the U.S. Total 2015 emissions from cement manufacturing were 68.8 million metric tons. If we say then that total GHG emissions in the U.S. were 6.1 billion metric tons, then the emissions from cement production represent only 1.13% of the total.
Now certainly the mining of aggregate and the production and delivery of concrete generate some additional greenhouse gases. And cement plants in developing and third-world countries are inefficient and more polluting than U.S. plants (the Portland Cement Association says that worldwide cement manufacturing generates about 3% of global GHG emissions). But when you consider the benefit to society of concrete and the long life-cycle and sustainability of concrete structures, this is a small price to pay. We need to be out there telling this story!
This was originally posted at Concrete Construction.