Changes to building materials could store carbon dioxide for decades

Replacing conventional building materials with materials modified to store carbon dioxide could move the planet closer to net-zero greenhouse gas emissions, according to a new study by Elisabeth Van Roijen and colleagues. The researchers calculate that full replacement of conventional building materials with these CO₂-sequestering alternatives could store as much as 16.6 ± 2.8 gigatons of CO₂ each year – an equivalent to about 50% of the anthropogenic CO₂ emissions in 2021. Removing carbon dioxide from the atmosphere, along with decreasing emissions, is important for slowing global climate warming. In pursuit of this removal, construction materials could provide a substantial CO₂ reservoir due to their widespread use and longevity. Van Roijen et al. calculate the global potential to store carbon in concrete, brick, asphalt, plastic, and wood with alterations such as mixing carbon aggregates in concrete or using bio-based materials in bricks. The researchers note that the carbon storing potential of these changes is more sensitive to the amount of material used (the cement aggregates store relatively little carbon but cement is used everywhere) than the quantity of carbon stored per unit mass of the building material. One challenge to overcome is the reluctance of builders to use new structural materials, fearing liability if these materials fail. Other challenges include finding enough carbon-sequestering minerals to use in these materials and establishing a rigorously monitored supply chain, as Christopher Bataille discusses in a related Perspective.