US: Researchers from CalPortland have published a peer-reviewed study looking at the absorption or carbonation of CO₂ by buildings, pavements and structures made from concrete. The authors argue that this negative effect on CO₂ emissions is not being considered in global, national and regional greenhouse gas accounting methods. The paper calls for focused studies on CO₂ uptake in concrete within the context of its overall Life Cycle Assessment (LCA).

“It is time to further examine the value of concrete in the built environment as a significant carbon sink,” said Allen Hamblen, president and chief executive officer (CEO) of CalPortland. “To do so accurately, we must specifically look at the net effects of CO₂ sequestration in concrete and evaluate all structures over their lifetime within a circular economy.”

The study looks at previous attempts to quantify the effect of concrete carbonation, notably using work by the Swedish Environmental Research Institute (SERI) that examined data from several European countries to develop practical models to gauge the extent of CO₂ uptake by concrete globally in the built environment. Different models estimated that 15 - 20% of CO₂ emissions from clinker production were reabsorbed over the lifetime of concrete structures.