Insight #1 – Carbon storage vs carbon sequestration.
‘Carbon storage’ / ‘carbon sequestration’ and ‘carbon sink’ are terms used (often loosely) to describe how buildings can reduce their net emissions. However there are important differences. Timber buildings do not sequester carbon during their life, they instead store carbon which has been sequestered by the forests and plants from which the building materials are made of, via photosynthesis. Cementitious building materials, e.g. concrete, do however sequester carbon during their life cycle through a chemical process called carbonation. However the amount of carbon sequestered is only a small fraction of the emissions generated from producing the material in the first place.
Insight #2 – How much carbon can buildings store?
The authors of this paper conclude that the cumulative carbon stored over the building’s life through upfront carbon sequestered in bio-based material and through carbonation of concrete is typically less than the emissions produced during operation of the building in a single year – ranging from negligible to 1.75. The significance of this however will change as operational carbon emissions reduce.
Insight #3 – The authors conclude that bio-based construction materials can make a contribution to climate change mitigation but are not a panacea.
Once again, more research is required!