Identified as one of the most challenging sectors to decarbonize, the construction industry faces a crucial task in curbing its substantial global emissions.
With rapid urbanization on a global scale, the world adds new buildings equivalent to the size of Paris every five days. Responsible for 37% of global emissions, the built environment prompted a response from the United Nations Environment Programme (UNEP) and the Yale Center for Ecosystems + Architecture, in collaboration with the Global Alliance for Buildings and Construction.
Their recently published report, “Building Materials and the Climate: Constructing a New Future,” unveils a comprehensive approach to reducing “embodied carbon” emissions from building materials. This solution is aimed at policymakers, manufacturers, architects, developers, engineers, builders, and recyclers.
The comprehensive report titled “Building Materials and the Climate: Constructing a New Future” presents a three-pronged solution for policymakers, manufacturers, architects, developers, engineers, builders, and recyclers.
This strategy aims to reduce “embodied carbon” emissions and mitigate negative impacts on natural ecosystems resulting from the production and deployment of building materials, such as cement, steel, aluminum, timber, and biomass, and is tabled as follows:
Avoid waste through a circular approach: building less by repurposing existing buildings is the most valuable option, generating 50-75 percent fewer emissions than new construction; promote construction with fewer materials and with materials that have a lower carbon footprint and facilitate reuse or recycling.
Shift to ethically and sustainably sourced renewable bio-based building materials, including timber, bamboo, and biomass. The shift towards properly managed bio-based materials could lead to compounded emissions savings in many regions of up to 40 percent in the sector by 2050. However, more policy and financial support is needed to ensure the widespread adoption of renewable bio-based building materials.
Improve decarbonization of conventional materials that cannot be replaced. This mainly concerns the processing of concrete, steel, and aluminum – three sectors responsible for 23 percent of overall global emissions today – as well as glass and bricks.
The report leads, urged that priorities should be placed on electrifying production with renewable energy sources, increasing the use of reused and recycled materials, and scaling innovative technologies. Transformation of regional markets and building cultures is critical through building codes, certification, labeling, and the education of architects, engineers, and builders on circular practices.
Implementing the three-pronged strategy necessitates sensitivity to local cultures and climates, considering the prevailing perception of concrete and steel as modern materials. Sheila Aggarwal-Khan, Director of UNEP’s Industry and Economy Division, emphasizes the need for a shift in industry action and the role of governments in achieving net zero in the sector by 2050.
“Until recently, most buildings were constructed using locally sourced earth, stone, timber, and bamboo. Yet modern materials such as concrete and steel often give only the illusion of durability, usually ending up in landfills and contributing to the growing climate crisis,” said Aggarwal-Khan.
“Net zero in the building and construction sector is achievable by 2050, as long as governments put in place the right policy, incentives, and regulation to bring a shift to industry action,” she added.
In addressing climate action in the building sector, the focus has primarily been on reducing “operational carbon” emissions. This includes heating, cooling, and lighting, set to decrease from 75% to 50% of the sector due to global decarbonization efforts.
As buildings source materials globally, reducing “embodied carbon” emissions requires a comprehensive approach, harmonizing measures across multiple sectors and each stage of the building lifecycle.
Effective government regulation and enforcement are crucial throughout the building life cycle, ensuring transparency in labeling, international building codes, and certification schemes. Investments in research and development, along with incentives for cooperative ownership models, are vital for the shift to circular economies.
“The decarbonization of the buildings and construction sector is essential for the achievement of the goal of limiting global warming to 1.5°C. By providing cutting-edge scientific insights as well as very practical recommendations to reduce embodied carbon, the study advances our joint mission to decarbonize the sector holistically and increase its resilience,” said Dr. Vera Rodenhoff, a key contributor to the study.
Civil and structural engineering play pivotal roles in achieving emission reduction goals within the construction sector. Here’s how:
Engineers can devise innovative designs that optimize material use, reducing overall carbon footprints. Incorporating sustainable and recycled materials into designs can significantly lower the environmental impact of construction projects.
Civil engineers can prioritize energy efficiency in building design and construction, integrating technologies that reduce energy consumption. Utilizing advanced materials with better insulation properties contributes to energy-efficient structures.
Structural engineers can conduct comprehensive life-cycle assessments, considering environmental impacts from material extraction to demolition. This approach ensures a holistic understanding of a building’s sustainability, aligning with the goals of the UN’s three-pronged decarbonization approach.