A new report commissioned by the United Nations Environment Programme (UNEP), as host of the Global Alliance for Buildings and Construction (GlobalABC), is calling for urgent action to reduce embodied carbon in construction materials as a critical step toward achieving global climate targets.
Funded by the German Federal Ministry for Economic Cooperation and Development (BMZ), the report forms part of UNEP’s broader initiative, “Transforming the Built Environment through Sustainable Materials,” and highlights the hidden but massive climate impact of materials like cement, aluminium, steel, bricks, and glass.
Embodied Carbon: The Hidden Emissions
Embodied carbon refers to the total greenhouse gas emissions associated with the lifecycle of building materials—from raw material extraction and manufacturing to transport, construction, maintenance, and end-of-life disposal. The report notes that 75% of these emissions stem from the manufacturing stage alone, with the remainder spread across transportation (13%), maintenance (11%), and construction (1%).
In 2021, the buildings and construction sector was responsible for over 34% of global energy demand and approximately 37% of energy and process-related CO₂ emissions. Materials used in the sector contribute 11% of total global GHG emissions—underscoring the scale and urgency of the challenge.
Investment and Innovation Required
The financial stakes are high. According to a McKinsey analysis of the Network for Greening the Financial System (NGFS) Net Zero 2050 scenario, a staggering $9.2 trillion per year must be spent globally on capital assets to reach net-zero. Of this, $2 trillion must be directed toward retrofits and improvements in existing assets in the construction sector, with $7.2 trillion needed for new, low-carbon construction.
The report emphasizes the critical role of low-carbon alternatives, which can cut emissions by 19%–46% in certain building types. Yet, despite the availability of promising technologies, key data on cost and carbon savings remain sparse—hindering informed decision-making across the construction value chain.
Gaps in Carbon Market Methodologies
As part of the study, 28 carbon market methodologies addressing both embodied and operational emissions were examined, identifying 10 focused specifically on embodied carbon. Fifteen projects across countries such as China, India, Argentina, Bangladesh, and South Africa were analyzed—showing emission reductions ranging from 0.069 to 0.49 tonnes of CO₂e per unit.
However, the report flags a significant gap: major carbon standards like VERRA and Gold Standard currently lack methodologies that directly address embodied carbon in buildings. Most embodied carbon projects identified were registered under CDM methodologies such as ACM005 and AMS.III.Z.
If the construction sector is to align with global net-zero pathways, embodied carbon must move to the forefront of climate action.
The report calls for comprehensive reform in carbon standards, mobilization of finance—including through carbon markets—and industry-wide adoption of low-carbon materials. Bridging these gaps is crucial for cutting the sector’s carbon footprint in half and ensuring a sustainable, resilient built environment by 2050.
