New Cement Sustainability Initiative (CSI) data for 2011 shows that the global cement industry has reduced its specific net CO2 emissions per tonne of cementitious product by 17% since 1990. This represents a serious amount of carbon prevented from entering the atmosphere. Using United States Geological Survey (USGS) world production data, if cement producers in 2011 were still emitting C02 at 1990 levels 456Bt of additional CO2 would have been released between 1990 and 2011.
Unfortunately there are a couple of problems.
Firstly, submitting data for the project is voluntary. As the CSI points out in its press release the data set comprises 55% of cement production outside of China. A rough calculation based on global cement production capacity suggests that this could only account for about one third of cement made. So how much carbon does the other two-thirds of cement made emit?
Secondly, although CO2 emissions per tonne of cement have gone down by a sixth since 1990, global cement production more than tripled (!) in the same time period. USGS data placed world production at 1.40Bt in 1990. It estimated 3.59Bt in 2011. In terms of net CO2 released into the atmosphere, in 1990 this was 1058Bt. In 2011 it was 2260Bt.
The big cement producers compare as follows to the CSI data, which reports emissions of 629kg/t. Lafarge reported 592kg/t cementitious in 2011 and 585kg/t in 2012. Holcim reported 584kg/t in 2011 and 579kg/t in 2012. HeidelbergCement reported 621kg/t in 2011. Cemex reported 612kg/t in 2011 and 2012. No data on specific net CO2 emissions were available for the major Chinese cement producers.
The CSI data shows that the cement industry has made an effort to reduce CO2 emissions since 1990. Yet this has been counteracted by a rise in cement production. To compensate for the rise in production between 1990 and 2011 the specific net CO2 emissions per tonne of cementitious product would have had to have fallen to below 300kg/t, a drop of 60%.
Environmentally sensitive readers shouldn't despair yet though as the CSI has demonstrated that emissions and production are gradually separating in the cement industry. From 2010 to 2011 specific net CO2 emissions per tonne of cementitious product fell from 638kg/t to 629kg/t. If this trend continues - and if it is representative for the cement producers the CSI doesn't cover – then the industry may be getting a handle on its emissions. We may be about to hit peak emissions for the cement industry sooner rather than later.
