The building sector may be overdue for a significant overhaul of the processes in which infrastructure is built to be more environmentally conscious and reduce carbon emissions, a new UN report reveals.
On September 12, 2023, the United Nations Environment Programme (UNEP) and the Yale Center for Ecosystems + Architecture (Yale CEA), under the Global Alliance for Buildings and Construction, released a new report that proposes solutions to decarbonize buildings and construction and reduce the waste generated.
The report, titled Building Materials, and the Climate: Constructing a New Future, provides a plan to policymakers, manufacturers, engineers, architects, developers, builders, and other stakeholders in what the report’s lead writer, Anna Dyson, Hines, Professor of Architecture at Yale University and Director of Yale CEA, calls the “building life cycle”. This is used to describe the stages of the building life cycle, from extraction of building materials to processing, installation, use, and demolition, or end-of-use.
“This is the first UNEP report that’s been led by architects, engineers, and builders, with respect to the building sector and materials sector,” Dyson said in a press briefing at the report’s launch.
The report presents its solutions to reduce carbon emission and waste through a three-pronged approach: Avoid waste through a circular approach by repurposing existing buildings or using materials with a lower carbon footprint; shift to earth- and bio-based building materials such as timber, bamboo, or sustainably-sourced bricks; and improve decarbonization methods on conventional materials that cannot be replaced, and re-evaluating building codes and standards in regional markets and building cultures across different countries.
If these measures can be adopted and adapted, then reducing embodied carbon in buildings to net zero can be achievable by 2050, the report claims. This can be achieved through making steps to decarbonize across every step of the building life cycle.
The building sector accounts for 37 percent of the world’s greenhouse gas emissions, thanks in part to the embodied carbon in modern building materials such as concrete, steel, and aluminum, which is generated during the production and use processes. Yet, complete decarbonization has been a challenge for this sector. As Dyson noted, the interdependencies throughout the stages of this building lifecycle complicate the process, as builders and other stakeholders may be more inclined to use the materials currently available and rely on current practices and codes in construction.
Mae-Ling Lokko, an assistant professor at Yale CEA, stated that increased use of alternative or biobased building materials, such as timber, bamboo, and locally sourced earth, in construction would see a decrease in carbon emissions. Lokko also notes that the supply currently outweighs the demand, but through raising awareness within the sector and through policy measures, the use could “accelerate a shift in norms in the building sector”.
Switching to renewable energy across all processes of the building lifecycle is also encouraged, along with reducing material use and supporting the transition to sustainable materials. As the report notes, this will involve “complex information management and communication across stakeholders”, which can be supported through policies that support the development and access to analytical tools.
The report states that governments and policymakers should, in their adoption of the Avoid-Shift-Improve solution, be sensitive to local cultures and climates, including in their relation to modern materials like concrete and steel. In case studies from Canada, Finland, Ghana, Guatemala, India, Peru, and Senegal, the ways in which decarbonization manifests through this model are noteworthy in their differences. Developed economies could devote resources to renovating existing aging buildings, while emerging ones can leapfrog carbon-intensive building methods to alternative low-carbon building materials.
The significance of policy reform in this sector was underscored during the press briefing. In addition, incentivizing the shift to biobased building materials and renewable energy sources during the extraction stage of the lifecycle would also be needed to kickstart the changes needed. The implementation of good policies and financial incentives could “encourage the re-use marketplace”, according to Naomi Keena, an assistant professor at McGill University’s School of Architecture. The use of secondary materials, for instance, could be supported through policies to enhance wider social acceptance.
In order to energize the market and relevant stakeholders to support the decarbonization of building materials, the tools to support these moves must be developed rapidly, and they must be supported through access to quality data and transparency. This can be strengthened through government regulation and enforcement and by investing in the research and development of nascent technologies. The research and tools should also be made readily available across the formal and informal parties in the building. As the report notes, in the informal sectors, stakeholders do not have access to the data nor the means to conduct their own analyses, which puts builders and producers in developing economies at a greater disadvantage in decarbonizing their outputs.
The report concludes on the note that international cooperation is critical in setting the standards for fair certification and accountability and setting the global standards for decarbonization. Noting that the responsibility for total decarbonization must be spread across producers and consumers within the formal building sector, both public and private.
What the UNEP report and its writers reveal is the hope that net zero carbon emissions can be reached. That the tools, materials, and practices already exist; the sectors need only to adopt and adapt them as needed. Even as the cultures around the building industries may vary across regions, the stakeholders may be united in wanting to play their part in reducing carbon emissions by 2050.
Naureen Hossain is an IPS correspondent based in New York.
