With urbanization on the rise worldwide, a concerning trend is emerging: every five days, the world witnesses the addition of buildings equivalent in size to the entire city of Paris. These rapid developments have grave implications for the environment, as the built environment sector currently accounts for a staggering 37 percent of global emissions. In response to this alarming situation, the United Nations Environment Programme (UNEP) and the Yale Center for Ecosystems + Architecture (Yale CEA), in collaboration with the Global Alliance for Buildings and Construction (GlobalABC), have released a groundbreaking report offering innovative solutions to decarbonize the buildings and construction sector while minimizing waste generation.
Titled “Building materials and the climate: Constructing a new future,” this report serves as a comprehensive guide for policymakers, manufacturers, architects, developers, engineers, builders, and recyclers. It introduces a three-pronged strategy to tackle the issue of “embodied carbon” emissions and mitigate the detrimental effects of building material production and deployment:
Avoid Waste Through a Circular Approach:
The report underscores the immense value of repurposing existing buildings, which generates 50-75 percent fewer emissions compared to new construction. This circular approach promotes sustainability by reducing waste while encouraging the use of fewer materials and those with a lower carbon footprint. The ultimate goal is to facilitate reuse and recycling.
Shift to Ethical and Sustainable Bio-Based Building Materials:
A critical aspect of the strategy involves transitioning to renewable, bio-based building materials, including timber, bamboo, and biomass. Such a shift has the potential to yield compounded emissions savings of up to 40 percent in the sector by 2050. However, this transition necessitates increased policy and financial support to encourage the widespread adoption of these eco-friendly alternatives.
Improve Decarbonization of Conventional Materials:
The report highlights the need to enhance the decarbonization of conventional materials like concrete, steel, aluminum, glass, and bricks. These materials, responsible for 23 percent of global emissions, demand immediate attention. Priority actions include electrifying production processes using renewable energy sources, increasing the use of recycled materials, and scaling up innovative technologies. Additionally, transforming regional markets and building cultures is crucial, which can be achieved through the implementation of building codes, certification programs, labeling, and educational initiatives for architects, engineers, and builders focused on circular practices.
The “Avoid-Shift-Improve” approach advocated by the report is a comprehensive strategy that must be adopted throughout the entire building process. By doing so, emissions can be significantly reduced, and the well-being of both humans and diverse ecosystems can be preserved. Furthermore, the successful implementation of this strategy requires a nuanced understanding of local cultures and climates, acknowledging the widespread perception of concrete and steel as modern building materials of choice.
Sheila Aggarwal-Khan, Director of UNEP’s Industry and Economy Division, emphasizes, “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 the industry’s action.”
Historically, climate action in the building sector has primarily focused on reducing “operational carbon” emissions related to heating, cooling, and lighting. As global decarbonization efforts advance, these operational carbon emissions are projected to decrease from 75 percent to 50 percent of the sector’s emissions in the coming decades.
To effectively address “embodied carbon” emissions, a holistic approach encompassing every phase of the building lifecycle is imperative, from material extraction to processing, installation, use, and eventual demolition. Government regulations and enforcement play a pivotal role in ensuring transparency through labeling, international building codes, and certification schemes. Investments in research and development, coupled with stakeholder training, are necessary, as well as incentives for collaborative ownership models among producers, builders, owners, and occupants to promote the shift towards circular economies.
Dr. Vera Rodenhoff, Deputy Director General for International Climate Action and International Energy Transition of the German Federal Ministry for Economic Affairs and Climate Action, underscores the report’s importance, stating, “The decarbonization of the buildings and construction sector is essential for the achievement of the goal of limiting global warming to 1.5°C.”
The report also presents case studies from various countries, including Canada, Finland, Ghana, Guatemala, India, Peru, and Senegal, showcasing the successful implementation of “Avoid-Shift-Improve” strategies. Developed economies are investing in the renovation of existing aging buildings, while emerging economies are embracing low-carbon building materials as alternatives to carbon-intensive construction methods.
Cities worldwide are poised to lead the charge in decarbonization efforts. Many urban centers are already incorporating vegetated surfaces, such as green roofs, façades, and indoor wall assemblies, to reduce urban carbon emissions, enhance urban biodiversity, and improve building energy efficiency.
In conclusion, the report serves as a vital roadmap to address the colossal carbon footprint of the building and construction sector. By embracing these strategies and prioritizing sustainability, the world can work collectively towards a more sustainable and resilient future while significantly contributing to global climate goals.