Engaging Suppliers to Reduce Scope 3, Category 1 Emissions: Building Capacity

Companies that actively engage their value chain to reduce greenhouse gas emissions—meaning that they work with partners across their upstream (suppliers) and downstream (distributors, customers) to drive sustainability improvements—are significantly more likely to achieve their Scope 3 reduction targets than companies that do not.¹

Of the 15 types (“categories”) of value chain emissions, Category 1—emissions from purchased goods and services—is applicable to every company, and it often holds significant potential for emissions reductions. For this reason, engagement with suppliers to reduce Category 1 emissions is often a necessary, and effective, emissions reduction strategy.

However, companies face common obstacles in building the capacity needed to drive reductions in this area that are meaningful enough to meet ambitious Scope 3 targets – such as Science-based Targets or other stakeholder reduction requirements.

Below, G&A’s analysts present solutions to five hurdles that clients often share with us  regarding Scope 3, Category 1 emissions reductions.

Common Hurdle #1: “We have hundreds (or thousands) of suppliers! There is no way we can reach out to all of them.”

The Solution: The good news is that you don’t need to. Start by establishing a baseline using the spend-based method — a practical and accessible approach that applies industry-average emission factors to your existing procurement spend data to estimate Category 1 emissions across your entire supplier base. No outreach required, no new data to collect from suppliers. If you already have spend data by supplier or category (and most companies do), you have everything you need to get started.

While the spend-based method relies on averages rather than supplier-specific figures, it gives companies a credible, GHG Protocol-aligned starting point for understanding the scale of their supply chain footprint — and it’s widely accepted as the appropriate methodology for companies in the early stages of building their Scope 3 inventory.

How G&A Can Help: Our team can help you quickly establish a spend-based baseline for your Category 1 emissions using relevant emission factors in line with the GHG Protocol.

Common Hurdle #2: “We need to show reduction in Category 1 emissions, but the spend-based calculation method doesn’t capture supplier-specific changes year-over-year.”

The Solution: To meaningfully track changes in Category 1 emissions, you need to directly engage your suppliers to obtain supplier-specific emissions factors. While the spend-based method described above provides a ballpark estimate of supplier emissions, it relies on industry averages, which limits your ability to identify and report supplier-specific emissions reductions over time.

How G&A Can Help: G&A provides the tools, resources, and expertise needed to effectively identify your priority suppliers to engage, conduct outreach to obtain the specific data needed, and incorporate supplier-specific Category 1 data into your inventory.

“Because the bulk of corporate GHG emissions are typically concentrated in Scope 3—often in Category 1—many companies set supplier engagement Scope 3 targets with SBTi, expanding responsibility for decarbonization from just their company to suppliers along the value chain. Bringing suppliers along the emissions reduction journey is essential to achieving Scope 3 targets.”

– Annie Roberts, G&A SVP, Climate Consulting

Common Hurdle #3: “Our procurement team is focused on quality, price, and efficiency. They aren’t familiar with the topic of sustainable procurement and can’t lead this work.”

The Solution: Empower buyers to pursue GHG emissions reductions through their purchasing decisions by providing targeted training to build comfort with best practices in sustainable procurement.

How G&A Can Help: Our team of sustainability experts works with companies to identify high-impact supplier engagement opportunities, such as focusing on emissions-intensive materials or high-volume suppliers. Through targeted training sessions and workshops, we help procurement teams understand and apply best practices in sustainable procurement. We will work with you to design a roadmap that aligns your purchasing team around an appropriate goal and ensures they have access to the right tools—creating confident buyers who understand the unique role they play in reducing emissions.

Common Hurdle #4: “Our suppliers don’t track sustainability metrics. We can’t ask them to add this to their plate.”

The Solution: Educate suppliers on the importance of emissions tracking through workshops or other training materials, and how it will increase their competitive advantage. Chances are that your company is not the only one asking your suppliers for sustainability data. Work with them to help identify how to start, what they can do over time, and what support they need.

How G&A Can Help: At G&A, we develop custom content and solutions tailored to your suppliers’ unique needs. We can help you meet your suppliers where they are in their sustainability journey, while encouraging improvement where needed and rewarding progress along the way. In addition to providing supplier identification, data collection and analysis, and GHG inventory support to clients and their suppliers, we’re also dedicated to co-creating solutions targeted toward your company’s specific needs.

Common Hurdle #5: “Our suppliers receive competing data requests from various customers, which creates challenges in timely data collection and metric alignment.”

The Solution: Streamline the request by focusing on the basics—GHG information first. Review supplier sustainability requirements from the top organizations in your industry or recommended best practices from your industry group.

How G&A Can Help: We help clients identify the necessary data points to request from suppliers to support their own disclosures. Our experience working with complex supply chains across industries has deepened our expertise in commonalities across supplier information requests by industry. We can work with you to design a program that is responsive to the current state of your industry while promoting increased ambition over time.

Taking the next step

Reach out today to discuss how we can work together to manage and reduce your supply chain emissions. For more information on Scope 3 emissions, and climate action more broadly, check out these resources:

• Scope 3 GHG Emissions Inventory
• Strategic Approaches to Reducing Scope 3 Emissions (Quick Reference Guide)
• ABCs of Corporate Climate Action (Quick Reference Guide)

1 – According to EcoVadis and Boston Consulting Group (BCG) 2025 ‘Carbon Action Report’.
2 – Supplier Engagement Guidance, GHG Protocol (2022)

ABOUT NEIL BRADLEY
Sustainability Analyst, G&A Institute

Neil Bradley is a Sustainability Analyst at Governance & Accountability Institute. His role is primarily focused on sustainability report development, ESG news research and analysis, and supporting a variety of additional client projects ranging from nature-related risk assessment to ESG datapoint gap analyses.