Up to 8% of all global anthropogenic human-made emissions are due to just one material, cement. And our use of it is rising.
The cement and concrete industry is encouraging this use, for example, by claiming that using concrete will reduce the “whole life” carbon emissions from buildings.
The absence of regulations to measure this has allowed such claims to play an important role in persuading designers and specifiers to use certain products. However, research conducted by my colleagues and me shows that these claims are often, at the least, exaggerated.
We identified the use of three such claims. First is the claim that because concrete has a high thermal mass, which allows it to act as a heat store, it will reduce the carbon emissions from heating and cooling a building during its life.
The second claim is that concrete is more durable than other materials, and that therefore concrete buildings will last longer, reducing the need to build new. The third is based on the ability of concrete to undergo carbonation, in which carbon dioxide is slowly absorbed from the atmosphere. This means that concrete can be seen as a “carbon sink”, and so is a sustainable choice.
These messages, among others, are promoted by the Mineral Products Association (MPA), the UK’s trade association, through their technical guidance and their sector roadmap to “beyond net zero”. Similar messages have been repeated by the European concrete industry.
Our research reveals a very different picture.