Sustainable Building Materials

Operational energy use in buildings accounts for approximately 30% of global energy consumption, increasing to 34% when including the energy used for producing cement, concrete, steel, and aluminum for construction ⁽⁸⁾. The CO₂ emissions associated with the entire lifecycle of these materials — from production to construction to usage to end of use — are called “embodied emissions.” In 2022, these embodied emissions represented 6.8% of global CO₂ emissions ⁽⁸⁾. This figure is raised to 10% when including the emissions from the production of bricks, glass, and copper ⁽¹⁴⁾.

The share of embodied emissions is expected to rise significantly going forward. The Global Alliance for Buildings and Construction (GlobalABC) projects that global raw material consumption will nearly double by 2060 under a “business-as-usual” scenario, with one-third of this growth driven by the construction sector ⁽¹⁴⁾. In this scenario, the share of embodied CO₂ emissions in total building emissions will almost double between today and 2060 ⁽¹⁴⁾. The construction industry thus risks becoming locked into a high-carbon development trajectory.

Rapid reductions in embodied emissions are essential to limit global warming to below 1.5°C [2.7 °F]. GlobalABC suggests three key approaches: avoiding waste and building with less new material, reuse of construction elements, shifting to bio-based building materials, and improving design for disassembly for conventional building materials and processes.

Avoiding waste and building with less new material means transitioning to a circular economy. The most significant opportunity for this lies in the planning and design stage. By integrating circular design strategies early in the construction process, embodied emissions can be reduced by 10–50%. Another lever is to design buildings for flexible use, allowing a building’s lifespan to be extended.

Shifting to earth or bio-based building materials is another approach that offers significant potential for decarbonization. For instance, using bio-based options like timber, bamboo, hemp, and straw can reduce emissions by up to 40% compared to conventional materials, provided these resources are harvested and processed sustainably.

Despite these new approaches, there is also the need to improve conventional building materials and processes. For cement and concrete, reducing clinker content, electrifying production, and using alternative binders can reduce emissions by up to 25%. Recycling steel reduces 60–80% of energy consumption and associated emissions. However, the growing gap between scrap supply and demand ensures that primary steel production will remain necessary. By transitioning to direct reduced iron technology and electric arc furnaces powered by renewables, emissions from primary steel production can be reduced by up to 97%. Decarbonizing aluminum production depends on renewable-powered production and increased recycling, potentially reducing energy use and associated emissions by 70–90%. Glass production can be decarbonized through electrified production and stricter recycling policies. Plastic decarbonization requires improved recycling methods and the development of bio-based and biodegradable plastics ⁽¹⁵⁾. Achieving all of this will require greater coordination between producers and consumers, including manufacturers, architects, developers, communities, and occupants. Strong policy support, regulations, and incentives across all stages of the material lifecycle, from production to end-of-use, are hence essential.