An international study with EPFL researchers suggests that large reductions in carbon emissions from cement and steel building materials may be achievable by 2050 using already-existing construction technologies.
Production of construction materials contributes up to 17% of human-made carbon dioxide (CO2) emissions each year, and most materials used in construction today are cement-based. Biobased materials like timber can't replace this massive need sustainably, so it is often assumed that generating housing and infrastructure to support fast-growing populations - especially in low- and middle-income countries - will drive carbon emissions upward.
An international team of researchers, including those from the Laboratory of Construction Materials (LMC) in EPFL's School of Engineering, has conducted a study that reframes this concern by examining alternative development pathways. In collaboration with experts from the UK, Austria, Germany and the US, the EPFL team combined historical global growth and construction trends with detailed forecasts of housing and infrastructure needs, particularly in low- and middle-income countries. They found that cement and steel use typically rise as countries develop, and then level off as infrastructure becomes established.
"This means that how materials are designed, produced, and recycled during periods of growth matters enormously for long-term emissions," says LMC head Karen Scrivener. "Our results suggest that improvements in these areas can already deliver large reductions in carbon emissions." The research has been published in Nature Communications.
A critical window for action
In their study, the researchers estimate that widespread adoption of existing sustainable construction technologies could reduce carbon emissions from cement-based materials and steel by about 73% compared to business as usual. These technologies include more efficient structural design and concrete production practices that reduce waste, as well as greater reliance on steel and concrete recycling powered by renewable electricity. Another priority is replacing clinker, the high-emissions component of cement, with low-carbon cementitious materials.
The team's novel use of combined historical and projected construction data for both buildings and infrastructure, as well as their focus on already-available technologies, makes their results particularly relevant for policymakers. At the same time, the authors stress that even the large emissions cuts that could be achieved without waiting for new inventions would not eliminate construction material emissions entirely. This would require more advanced technologies like large-scale carbon capture. Additionally, in many regions where future construction demand will be highest, regulatory frameworks, market incentives, and industrial capacity must become aligned with low-carbon construction practices.
"Our work suggests that large-scale decarbonization of construction materials is technically possible alongside the expansion of essential housing and infrastructure - with the right policies," says LMC researcher Alastair Marsh. "The coming decades represent a critical window to update standards to allow material-efficient design and lower-clinker cements, and to scale practical solutions for low- and middle-income countries, where future demand will be concentrated."
