Scope 3 Category 6: Business Travel
Category 6 (business travel) covers emissions from employee travel by air, rail, road, and sea for business purposes. It is typically one of the most straightforward Scope 3 categories to measure — data exists in travel management systems and expense reports — but is frequently undercalculated due to incomplete data collection.
Category 6 (business travel) covers emissions from employee travel by air, rail, road, and sea for business purposes. Category 6 covers all employee travel for business purposes in vehicles not owned or operated by the company.
What Category 6 covers and what it excludes
Category 6 covers all employee travel for business purposes in vehicles not owned or operated by the company. This includes: commercial flights (economy, business, first class); rail journeys (domestic and international); rental cars and car hire; taxis, rideshares, and ground transportation; ferries and other commercial maritime passenger transport; and hotel and accommodation stays at business travel destinations.
Category 6 excludes: employee commuting (Category 7); company-owned or leased vehicles used for business travel (Scope 1 for fuel; Scope 3 Category 8 for leased vehicles); and employee-owned vehicles used for business travel where the company reimburses mileage (these are Scope 3 Category 6 under the GHG Protocol — the vehicle ownership does not matter, the purpose does).
Hotel stays: accommodation emissions are included in Category 6 under GHG Protocol. Use DEFRA hotel emission factors (kg CO2e per room night, by hotel star rating and country) to calculate accommodation-related emissions. Many companies omit hotel stays from Category 6 — this is a gap that assurers increasingly flag.
Aviation emissions — the radiative forcing debate
Aviation emissions are more complex than other travel modes due to radiative forcing — the additional warming effect of contrails, cirrus cloud formation, and NOx emissions at altitude. These non-CO2 effects amplify the climate impact of aviation beyond the CO2 emissions alone.
The IPCC estimates the total climate impact of aviation is approximately 2–4x the CO2 effect alone. The GHG Protocol Scope 3 Standard recommends applying a radiative forcing index (RFI) or uplift factor of approximately 1.9–2.7 to aviation CO2 emissions to account for these effects.
DEFRA GHG Conversion Factors include both CO2-only and CO2e (with radiative forcing) aviation factors — use the CO2e factors for a complete picture. However, the science on radiative forcing quantification remains uncertain, and some reporting frameworks (including some ESRS assurers) prefer CO2-only aviation figures supplemented by a qualitative disclosure of non-CO2 effects.
Best practice: report both CO2-only and CO2e (with radiative forcing) aviation figures, disclose the RFI applied, and note the scientific uncertainty. This satisfies both strict GHG Protocol guidance and assurer expectations for transparent methodology disclosure.
Reducing Category 6 — travel policy and virtual meetings
Category 6 reduction is primarily achieved through travel policy changes and investment in virtual meeting infrastructure rather than capital investment.
Travel policy levers: mandatory virtual meeting assessment before booking flights; economy class default with business class approval process; rail preference over short-haul flights where journey time is comparable; carbon budgets per employee or per team; and travel emissions included in department sustainability reporting.
COVID-19 as a natural experiment: the pandemic forced near-elimination of business travel and demonstrated that many meetings could be conducted virtually without significant productivity loss. Post-COVID, most companies have maintained lower business travel levels than 2019 — Category 6 reduction has been one of the most achievable Scope 3 improvements.
For ESRS E1-3 action disclosure: if you have implemented travel policies that have reduced Category 6, quantify the emission reduction achieved and include it in your climate action disclosure. A 30% reduction in business travel emissions is a specific, verifiable, funded action that strengthens your transition plan credibility.
Frequently asked questions
Do we include emissions from employee-owned cars used for business travel?
Yes — when employees use their personal vehicles for business travel and are reimbursed by the company (per-mile or per-km), those emissions are Category 6. Use DEFRA vehicle emission factors for the vehicle type or a standard average car factor if vehicle type data is unavailable.
How do we get travel data from our travel management company?
Most corporate travel management companies (TMCs) — Amex GBT, CWT, BCD — provide annual GHG emission reports as a standard service. These reports include flights, hotels, and rail booked through the TMC. Emissions from travel booked outside the TMC (direct bookings, expense claims) must be supplemented from expense report data.
Should we use short-haul or long-haul emission factors for flights?
Use distance-specific emission factors. DEFRA provides separate factors for short-haul (<3700 km), long-haul (>3700 km), and domestic flights. Apply the appropriate factor based on the flight distance for each trip. If you only have aggregate flight data without distance breakdown, use a weighted average factor based on your typical flight mix — disclosed as an estimation methodology.