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sustainable supply chain in construction | Tunley Environmental

Written by Tunley Environmental | 9 Jul 2025

Under increased pressure from regulators, investors and clients, companies in the built environment have become more incentivised to take into account upstream emissions from the supply chain in the drive to decarbonise their operations. Together, operational, embodied and user carbon make up what is referred to as whole life carbon (WLC). According to the UN Environment Programme, as of 2021, operational carbon accounted for approximately 28% of global CO₂ emissions, while embodied carbon contributed a further 12%, highlighting the significant footprint of both in the built environment. Globally, supply chains contribute to roughly 60% of total greenhouse gas emissions. Building a sustainable supply chain in construction can be central to achieving net zero targets, meeting compliance and achieving long-term business resilience. One of the most effective tools for doing this is a whole life carbon. When properly implemented, a WLCA enables contractors, procurement teams and project developers to make data-informed decisions that reduce environmental impacts. 

What is a WLCA? 

A Whole Life Carbon Assessment (WLCA) is a comprehensive methodology used to assess the carbon footprints of built assets, such as infrastructure and buildings, at every stage of their life cycles. This includes the extraction and production of building materials, as well as their design, construction, operation, and maintenance while in use, as well as their final deconstruction, disposal and possible reuse. The Royal Institution of Chartered Surveyors (RICS) defines ‘WLCA’ as the calculation and reporting of carbon impacts throughout all lifecycle stages of a built asset, including potential benefits beyond the system boundary. 

Optioneering, the systematic assessment of several design options, material specifications, and supply chain options early in the project lifetime, is one of the most significant contributions of a Whole Life Carbon Assessment (WLCA). WLCAs incorporate carbon performance into the decision-making process when there is still room to affect results by measuring emissions during the concept and early design phases. For example, depending on supplier methods, geographic sourcing, and material composition, the environmental effect of a single functional element—like a wall or roof system—can vary greatly. Having early awareness of carbon hotspots and trade-offs is crucial to creating a construction supply chain that is genuinely sustainable. Another key feature of a WLCA is its emphasis on repetition and learning from repeated action. This iterative process enables informed decisions while helping to refine carbon reduction targets, design choices, construction methods and financial impacts. 

Why Does Supply Chain Sustainability Matter for a WLCA? 

Supply chain decisions significantly impact both embodied and operational carbon and contribute to sustainability in the construction industry. Modules A–C4 together represent the stages of embodied carbon, covering all emissions associated with material production, transport, construction, use-phase maintenance, and eventual end-of-life processing. The WLCA modular framework allows for detailed analysis under separate sections:  

  • Module A captures upfront embodied carbon, including raw material extraction, manufacture and on-site construction impacts. 
  • Module B (excluding B6–B8) addresses in-use embodied emissions, such as maintenance, repair, replacement and refurbishment over the asset’s lifespan. 
  • Module C accounts for the end-of-life stage, including deconstruction, transport, waste processing, and final disposal. 
  • Modules B6–B8, on the other hand, represent operational and user carbon, relating to energy and water consumption during use (B6 and B7) and user-related activities (B8) 
  • Module D encompasses aspects outside project scope like exported energy 

Integrating supply chain sustainability into WLCAs offers several benefits including: 

  • Environmental impact optimisation through efficient resource use 
  • Cost efficiency by identifying long-term carbon reduction solutions 
  • Regulatory compliance with carbon disclosure programmes 
  • Meeting stakeholder expectations for sustainable practises 

Additionally, specifying materials with excellent carbon scores becomes meaningless if these aren't readily available from manufacturers or lack Environmental Product Declarations (EPDs). Therefore, sustainable procurement strategies must consider the entire supply chain to effectively reduce whole life carbon emissions. 

Learn More: Benefits of a Sustainable Supply Chain | Tunley Environmental 

Using WLCAs to Assess Suppliers and Materials 

WLCAs give organisations a clear and standard way to compare suppliers and products when they want to develop a strategy to enhance their sustainable supply chain in construction: 

Material Carbon Intensity 

Companies can evaluate the carbon emissions from the extraction, transportation and subsequent manufacturing of raw materials into construction materials using EPDs. Environmental Product Declarations (EPDs) provide standardised carbon data for construction materials and products. These third-party verified documents summarise lifecycle assessment results in a transparent, comparable format.  Data from these insights assist purchasers and specifiers in making choices that satisfy design and performance criteria while lowering embodied emissions. 

Integrating WLCAs into the Supply Chain 

Follow these steps to embed a WLCA into procurement in your construction projects: 

Step 1: Establish Internal Carbon Governance 

Create cross-functional groups across sustainability, design and procurement to manage suppliers and drive sustainable supply chains in construction. At every RIBA stage, clearly define the WLCA goals and roles. 

Step 2: Mandate Carbon Declarations 

Update procurement policies to require additional requirements like third-party verified EPDs, carbon intensity benchmarks and carbon reduction plans for key suppliers. 

Step 3: Use Dynamic WLCA Tools and Third-Party Verification 

Adopt software or consulting support that can model WLCA data in real time. Tunley Environmental’s WLCA service, for example, offers a carbon management plan that conducts life cycle assessments at every key stage of a project. In line with RIBA plan of work. 

Step 4: Build Supplier Capacity 

Not every provider will be prepared for a WLCA. Consider investing in development and upskilling of Tier 1 and Tier 2 providers with the company’s objectives for sustainable procurement. 

How WLCAs Support Compliance with Industry Standards 

Regulations like PAS 2080 require construction companies to prove their commitment to sustainability based on established guidelines. For companies seeking to build a sustainable supply chain in construction in line with industry regulations, WLCAs can support this by: 

  • Providing a robust basis for supplier impact disclosures 
  • Enabling early-stage carbon modelling across the asset lifecycle 
  • Supporting collaborative decision-making with suppliers 
  • Facilitating carbon management throughout design, construction and operation 

Partially to encourage sustainable construction practices in the industry, PAS 2080 establishes a common approach for managing whole life carbon among infrastructure sectors and value chain members. This framework impacts early intervention, accurate data collection and long-term thinking to ensure infrastructure resilience and low-carbon legacy. Major infrastructure providers in the UK now require PAS 2080 certification, creating a ripple effect throughout supply chains.

The Bottom Line

WLCAs play a large role in supply chain sustainability, giving construction professionals a structured way to understand both embodied and operational carbon effects. This approach changes focus from single emission points to the entire lifecycle of a built asset, enabling better carbon reduction strategies for sustainable construction projects. The difference between lifecycle modules, from material production through operational use to end-of-life factors, allows targeted actions at each supply chain stage. WLCA provides the evidence, structure and strategic advantage to help successfully manage a sustainable supply chain in construction. To learn more about we can support you with WLCA, visit this page.