Does the Science-Based Targets Initiative (SBTi) Require Companies to Measure Employee Travel Emissions in Their Net-Zero Plans?

Yes, if business travel and commuting are material. Under the SBTi Corporate Net-Zero Standard, companies must set targets that cover Scope 3 when it exceeds 40 percent of total emissions. Near-term targets must include at least 67 percent of Scope 3, and long-term targets require 90 percent or greater absolute reductions across Scopes 1, 2, and 3 by 2050. This typically includes Category 6 (business travel) and Category 7 (employee commuting), so you need a plan to measure, reduce, and report these emissions.

The GHG Protocol Corporate Value Chain (Scope 3) Standard requires consistent quantification methods, and Europe's CSRD/ESRS framework requires disclosure by category where material. CSRD mandates limited assurance from third-party auditors starting 2025, with reasonable assurance required by October 2028. This means you need documented emission factors, data sources, and calculation methods from the start.

How to Measure Employee Travel Emissions Accurately

Start by defining your boundary. Include all company-paid trips (air, rail, road) and hotel stays, and decide whether to include meetings and events separately. For commuting, include regular home-to-office travel and typical hybrid patterns, like three office days per week.

Choose your calculation method by mode. For flights, use distance-based calculations with great-circle distance (the shortest path between two points on Earth's surface), aircraft type where available, and class-of-service multipliers. For rail and bus, use distance-based factors by region. For rental cars and taxis, use fuel- or distance-based factors. When you only have spent data, use it as a fallback and improve over time.

US emission factors (EPA 2025)

Flights:

• Short (<300 miles): 0.456 lbs CO2e per passenger-mile
  
• Medium (300-2,300 miles): 0.284 lbs CO2e per passenger-mile
  
• Long (>2,300 miles): 0.359 lbs CO2e per passenger-mile
  

Ground:

• Car: 0.655 lbs CO2e per mile
  
• Amtrak: 0.212 lbs CO2e per passenger-mile
  
• Commuter rail: 0.293 lbs CO2e per passenger-mile
  
• Bus: 0.145 lbs CO2e per passenger-mile
  

Report final inventories in metric tons CO2e (1 metric ton = 2,204.6 lbs) for CSRD and SBTi compliance.

Sample trip calculation:

• NYC to Chicago round-trip: 1,580 miles × 0.284 lbs CO2e/mile = 449 lbs CO2e
  
• Two hotel nights (no HCMI data): 50 lbs CO2e/night × 2 = 100 lbs CO2e
  
• Airport taxi (30 miles): 30 × 0.655 lbs CO2e/mile = 20 lbs CO2e
  
• Total: 569 lbs CO2e (0.26 metric tons CO2e)
  

Prioritize data quality. Use supplier-specific emissions where independently verified, then distance-based calculations with verified factors, and finally spend-based estimates to fill gaps. Document your emission factors, versions, and sources.

US TMC realities:

Tier 1 (Supplier-specific): Rare. Major airlines provide CO2 estimates in corporate portals, but these are usually distance-based, not actual fuel burn. Hotels rarely provide property-level data.

Tier 2 (Activity-based): Most practical. TMCs like SAP Concur, Navan, and TravelPerk export itineraries with origin-destination, fare class, and hotel nights. Apply EPA or DEFRA factors. Accuracy: ±15-20 percent for flights, ±30-40 percent for hotels without HCMI.

Tier 3 (Spend-based): Last resort. EEIO factors for air transportation or accommodation vary 3-5× by source. Document which database you use.

For hotels, request HCMI footprints where available, but know that most US properties don't provide this data yet. HCMI covers on-site energy, refrigerants, and laundry but excludes upstream supply chain emissions—which can be 80 percent or more of a property's footprint. One 2025 study found HCMI estimates were 5× lower than comprehensive Scope 3 measurement. Use regional averages as fallback and tag them as "estimated pending supplier data."

Note on aviation non-CO2 impacts: The GHG Protocol doesn't require reporting contrails, NOx, or water vapor in official inventories, and SBTi uses CO2 only for aviation. Research suggests aviation's total climate impact is roughly 1.9-2.0× CO2 alone, but uncertainty is high. If you disclose non-CO2 effects, report them separately and label clearly. EPA factors include only CO2, CH4, and N2O.

Tools to Calculate and Manage Employee Travel Emissions

Most companies combine booking and expense data with a calculation engine. Your travel platform provides itineraries, distances, fare classes, and hotel nights. Expense systems fill gaps like taxis and ride-hail. HRIS data supports commuting models.

Platforms like SQUAKE, Thrust Carbon, Watershed, Normative, and Plan A integrate with TMCs to automate calculations, apply current factors, and version methodologies for audit trails. The GHG Protocol Scope 3 guidance explains category methods, and public factor libraries (EPA, UK government) help validate or backfill calculations.

Including Commuting When Measuring Employee Travel Emissions

Commuting is Scope 3 Category 7 and often material for office-based companies. Combine employee surveys for mode split and frequency with modeled distances from anonymized home-to-office postcode data, then apply regional emission factors. Badge swipes or desk bookings can improve the in-office day count for hybrid teams.

Sample annual commute (hybrid worker):

• 25-mile round-trip, 3 days/week, 48 weeks
  
• 3,600 miles/year by car × 0.655 lbs CO2e/mile
  
• Total: 2,358 lbs CO2e (1.07 metric tons CO2e)
  

Work-from-home energy (electricity, heating) is optional under GHG Protocol Category 7 because employees' home energy is their personal Scope 1/2, not the employer's Scope 3. Many US companies exclude it to avoid double-counting and because it requires intrusive employee data. If you include it, average home office energy is roughly 1,500-2,200 lbs CO2e annually per full-time remote worker using US grid averages. Document your methodology clearly.

For multi-country footprints, segment by location to reflect different transit grids and modal choices. Align disclosures to the GHG Protocol and ESRS: explain methods, data coverage, and exclusions, and update your model as commuting patterns change.

Easiest Ways to Measure Flight and Hotel Emissions for Staff

For flights, pull booked segments from your TMC, calculate great-circle distance per leg, apply aircraft and seat-class factors where available, and aggregate by trip and traveler. Use carrier-specific models if available, but maintain a consistent fallback so totals stay comparable year to year.

For hotels, start with room-nights by property and request HCMI footprints. Where hotels can't provide figures, apply market-and-region averages and tag them as "estimated" to upgrade later. Handle meeting space and catering emissions under events or supplier categories to avoid overlap.

For ground, capture rail segments natively from your TMC and use regional factors. For taxis and ride-hail, distance-based calculations from receipts work better than spend-based methods when possible. Calculate rental cars with fuel type and distance. As a fallback, use average fuel economy for the booked class and local fuel factors.

Standards Under SBTi, CSRD, and the GHG Protocol

Three frameworks guide how you measure and report employee travel emissions.

SBTi expects material Scope 3 categories—including business travel and commuting—to be measured and included in targets, with near-term coverage at 67 percent or more of Scope 3 and long-term reductions of 90 percent or greater by 2050.

The GHG Protocol defines categories, methods, and disclosure requirements.

CSRD requires a double materiality assessment, then detailed disclosure of Scopes 1, 2, and 3 with category-level details where material under ESRS E1. Document your methodologies, factor sources, data coverage, and plans to increase accuracy.

Practical Steps to Build a Measurement Program

Consolidate data feeds: Enable TMC exports for flights, rail, hotels, and cars. Add expense categories for taxis and ride-hail. Pull HR headcount and office days for commuting.

Choose methods and factors: Use activity-based calculations with EPA factors, request HCMI data for hotels where possible, and document factor sources and versions for auditability.

Build a quarterly cadence: Refresh data, track intensity metrics (lbs CO2e per trip or per FTE), and publish updates to keep leaders engaged.

Pilot reductions: Shift short-haul air to rail, promote economy-class default on flights under six hours, expand virtual meetings, and negotiate HCMI reporting in hotel RFPs.

With the right data, methods, and tools, measuring employee travel emissions becomes repeatable and useful. It helps travel, finance, and sustainability teams make better choices, show credible progress to SBTi, and meet CSRD expectations.

Explore practical examples in Dyme’s resources on CSRD timeline for US companies, sustainable business travel essential guide, and effective ways to reduce carbon emissions from business travel.