The authors make wrong assumptions on the contribution of OPC to world’s greenhouse gas emissions because they forget the contribution of carbon storage in OPC structures. Pade and Guimaraes (2007) estimate that for a 100 years life concrete structures can store around 28% of CO2 during 70 years life time and as much as 58% after demolition during 30 years. Also its far from truth that alkali activated materials are a low carbon technology, Turner & Collins (2013) prove that, Ouellet-Plamondon and Habert (2014) showed that only ´one part geopolymers` shows carbon footprint levels much lower than Portland cement based mixtures. Ouellet-Plamondon, C. ; Habert, G. (2014) Life cycle analysis (LCA) of alkali-activated cements and concretes. In Handbook of Alkali-Activated Cements, Mortars and Concretes, 663-686 (Eds) Pacheco-Torgal, F.; Labrincha, J.; Palomo, A.; Leonelli, C.; Chindaprasirt, P., WoodHead Publishing-Elsevier, Cambridge Pade, C.; M. Guimaraes, M. (2007) The CO2 uptake of concrete in a 100 year perspective. Cem. Concr. Res. 37, 1348–1356. Tuner, L.; Collins, F., Carbon dioxide equivalent (CO2-e) emissions: A comparison between geopolymer and OPC cement concrete. Construction and Building Materials 43 (2013) 125–130.