How to Collect Scope 3 Emissions Data from Suppliers

Collecting Scope 3 emissions data from suppliers requires identifying which suppliers matter most, deciding what data to request, reaching the right person at each supplier, and running a structured outreach campaign with persistent follow-up. For most manufacturers, Scope 3 (purchased goods and services, upstream transportation, and other supply chain activities) accounts for 70-90% of total greenhouse gas emissions. You cannot meet climate targets without this data, and you cannot get this data without supplier cooperation.

This guide covers how to plan and execute a supplier data collection campaign for Scope 3 reporting under CSRD, SBTi, CDP, or any framework that requires supply chain emissions data.

Why Scope 3 Data Collection Is Difficult

Scope 1 and 2 emissions come from your own operations and your purchased energy. You control the data. Scope 3 depends on hundreds or thousands of other companies providing information they may not track, may not want to share, or may not know how to calculate.

A sustainability lead at a Fortune 500 medical device company described the scale: after getting SBTi targets validated, the next step was engaging top suppliers on emissions data. The plan covered hundreds of suppliers initially, growing to 1,000+ over five years. Even with a focused campaign on the top 500, the response rate was 60%, leaving 200 suppliers unaccounted for.

That 60% is above the industry average of roughly 40% for supplier sustainability programs. The gap between “sent the request” and “received usable data” is where most companies get stuck.

Which Suppliers to Prioritize

You do not need emissions data from every supplier. Most frameworks allow you to focus on the suppliers that represent the majority of your emissions footprint.

The 75% Threshold

The GHG Protocol and SBTi both suggest engaging suppliers that collectively represent at least 75% of your Scope 3 emissions (by spend or by emissions estimate). In practice, this is typically your top 50-200 suppliers by spend, depending on how concentrated your supply base is.

Spend-Based Prioritization

If you do not have supplier-specific emissions data yet (which is the starting point for most companies), use procurement spend as a proxy. Rank suppliers by annual spend, calculate the cumulative percentage, and draw the line at 75%. This gives you a working list for your first campaign.

Sector and Category Risk

Some categories carry disproportionate emissions. Raw materials (metals, chemicals, plastics), energy-intensive manufacturing (castings, forgings, electronics), and transportation-heavy categories should be prioritized even if their spend is moderate. EEIO (Environmentally Extended Input-Output) models and industry benchmarks can help you identify these.

Practical Batching

Do not launch outreach to all prioritized suppliers simultaneously. Batch them into waves of 50-100 so your team can manage the responses, follow up effectively, and troubleshoot issues before scaling.

What Data to Request

The data request depends on your reporting framework and how mature your suppliers are. Here is a progression from simplest to most detailed:

Level 1: Basic Activity Data

For suppliers with no emissions tracking, request activity-level data that you can convert to emissions using standard factors:

Annual energy consumption (electricity, natural gas, fuel oil) in kWh, therms, or gallons
Location of primary manufacturing or operations facility (for grid emission factors)
Annual production volume or revenue (as a normalization metric)

This is the lowest-friction ask and gets you better data than spend-based estimates.

Level 2: Supplier-Calculated Emissions

For more mature suppliers, request their calculated Scope 1 and Scope 2 emissions:

Total Scope 1 emissions (metric tons CO2e)
Total Scope 2 emissions, market-based and location-based (metric tons CO2e)
Reporting year and methodology used
Whether data has been third-party verified

Level 3: Product-Level or Allocation-Based Data

For the most granular reporting, request emissions allocated to your specific products or business:

Emissions per unit of product or per revenue dollar
Life cycle assessment (LCA) data for specific materials or components
Upstream Scope 3 data from the supplier’s own supply chain

Level 3 is the gold standard but is unrealistic for most suppliers today. Start with Level 1 or 2 and build toward Level 3 over multiple reporting cycles.

How to Frame the Ask

Suppliers are more likely to respond when they understand why the request matters and what is expected of them. The framing should address three concerns:

Why You Need It

Be specific about the regulatory or business driver:

“Our company is required to report Scope 3 emissions under the EU Corporate Sustainability Reporting Directive (CSRD).”
“We have validated Science Based Targets and need supplier emissions data to track progress.”
“This data is required for our annual CDP climate disclosure.”

Do not bury the reason in a paragraph of corporate sustainability messaging. Lead with the regulatory requirement.

Why It Matters to Them

Suppliers need a reason to spend time on your request:

“Suppliers who provide emissions data will be prioritized in future sourcing decisions.”
“This data request will become an annual requirement. Responding now establishes the baseline and makes future requests easier.”
“We are offering free access to a carbon accounting tool for suppliers who participate.”

What Exactly You Need

Vagueness kills response rates. Specify:

The exact data fields (see Level 1, 2, or 3 above)
The reporting period (calendar year, fiscal year)
The format (spreadsheet template, online form, CDP response)
The deadline (specific date, not “at your earliest convenience”)

Provide a template or form. Suppliers are far more likely to respond when they can fill in specific fields rather than compose a response from scratch.

The CSRD Context

The EU Corporate Sustainability Reporting Directive (CSRD) requires companies to report detailed sustainability information, including Scope 3 emissions across their value chain. CSRD applies to approximately 50,000 European companies, plus their global supply chains. This means that even non-European suppliers will increasingly receive Scope 3 data requests from their European customers.

For companies reporting under CSRD, the European Sustainability Reporting Standards (ESRS) require disclosure of Scope 3 emissions by category. This is not optional and not estimated. Companies need actual supplier data to comply.

The timeline is accelerating. Large public companies began reporting in 2025, and the requirements cascade to smaller companies over the following years. Suppliers who do not engage now will face increasing pressure from multiple customers simultaneously.

Response Rate Benchmarks and What Drives Them

Typical response rates for Scope 3 supplier engagement campaigns:

Approach	Expected Response Rate
Generic email to existing contacts	15-25%
Targeted email to sustainability contacts	35-45%
Targeted email + structured follow-up	50-60%
Above + executive sponsorship + commercial leverage	65-80%

The sustainability lead at a Fortune 500 medical device company achieved 60% from the top 500 suppliers. That required dedicated effort and a structured campaign. The industry average for CDP supply chain responses is approximately 40-50%.

The gap between 40% and 80% is not about better email copy. It is about reaching the right person, following up consistently, and applying real consequences for non-response.

Follow-Up and Escalation

Plan for multiple follow-ups. Most suppliers will not respond to the first email.

Initial request (Day 0): Send the data request with template, deadline, and context.
Reminder 1 (Day 14): Resend to the same contact. Reference the original request.
Reminder 2 (Day 28): Try an alternate contact if the first has not responded. Offer a brief call to walk through the template.
Escalation (Day 42): Involve procurement or executive sponsors. Frame it as a business requirement.
Final notice (Day 56): Notify the supplier that non-response will be documented and factored into supplier risk assessments.

A Senior SQE at a Fortune 100 life sciences company described the pattern: “You reach out 2, 3, 4, 5 times. Nobody responds. You just give up.” The structured cadence prevents this. Automation makes it sustainable at scale.

Handling Non-Responders

After exhausting your outreach cadence, you still need data for reporting. Options for non-responding suppliers:

Spend-Based Estimation

Use EEIO emission factors to estimate emissions based on procurement spend and industry sector. This is the most common fallback method and is accepted by the GHG Protocol, CDP, and SBTi for suppliers where primary data is not available.

Industry Averages

Use published sector-average emission intensities (e.g., emissions per dollar of revenue or per unit of product). These are less accurate than supplier-specific data but provide a defensible starting point.

Hybrid Approaches

Use primary data from responding suppliers to calculate category-level emission intensities, then apply those intensities to non-responding suppliers in the same category. This is more accurate than pure spend-based estimation.

Document the Gap

Whatever method you use, document which suppliers provided primary data and which were estimated. Auditors and reporting frameworks expect transparency about data quality. Improving the ratio of primary to estimated data over time is itself a measurable goal.

Building a Multi-Year Program

Scope 3 data collection is not a one-time project. It is an annual (or more frequent) cycle that expands and deepens over time.

Year 1: Focus on top suppliers by spend. Collect Level 1 or Level 2 data. Establish baselines.
Year 2: Expand to additional suppliers. Improve data quality from Year 1 respondents. Begin requesting Level 2 data where you previously accepted Level 1.
Year 3+: Pursue product-level data from key suppliers. Integrate supplier emissions data into procurement decisions. Set supplier-specific reduction targets.

Each cycle should build on the previous one, increasing coverage, improving data quality, and strengthening the business case for supplier participation.

Where Bridgecurrent Fits

Bridgecurrent automates the two bottlenecks in Scope 3 supplier engagement: finding the right sustainability or environmental contact at each supplier, and managing the follow-up sequence at scale. Instead of staffing a team of 5-8 people for weeks just to source contacts, Bridgecurrent discovers and validates contacts automatically and runs the outreach campaign until suppliers respond or are flagged for escalation. See how automated supplier outreach works.