Category 6 — Business Travel covers GHG emissions from the transportation of employees for business-related activities in vehicles not owned or operated by the reporting company. This includes flights, train journeys, bus and coach travel, taxi and ride-hailing services, rental cars, and hotel stays.
What Is Included
Category 6 covers all business-related travel by employees where the transport is not in company-owned or controlled vehicles:
- Air travel: Domestic, short-haul, and long-haul flights (economy and business class)
- Rail travel: Intercity trains, commuter rail used for business trips
- Rental cars and taxis: Hired vehicles, taxis, and ride-hailing for business purposes
- Bus and coach: Long-distance coach travel for business
- Hotel stays: Energy used in hotel rooms during business travel (some frameworks include this as part of the overall business travel footprint)
Category 6 does not include travel to and from work (employee commuting - Category 7) or travel in company-owned vehicles (Scope 1). The test is: is the vehicle owned or controlled by the reporting company? If yes, it's Scope 1. If no, it's Category 6.
Calculation Methods
Distance-Based Method (Recommended)
Uses the distance travelled and an emission factor per passenger-km by transport mode. Data sources include airline booking systems, travel management companies (TMCs), and expense reporting.
Category 6 - Business Travel Emissions (Distance-Based)
Category 6 Emissions
Total emissions from employee business travel, in tCO₂e
Distance
Distance travelled per trip, in km
Passenger Count
Number of employees on the trip
Emission Factor
tCO₂e per passenger-km for the transport mode and cabin class
Spend-Based Method
Applies EIO emission factors per unit of spend on travel and accommodation. Used when detailed trip data is unavailable.
Emission Factors by Transport Mode
| Mode | Class / Type | Emission Factor (kgCO₂e/passenger-km) |
|---|---|---|
| Short-haul flight (<3,700 km) | Economy | 0.151 |
| Long-haul flight (>3,700 km) | Economy | 0.148 |
| Long-haul flight (>3,700 km) | Business | 0.429 |
| Rail (UK average) | - | 0.035 |
| Taxi (petrol, UK) | - | 0.149 |
| Rental car (medium petrol) | - | 0.168 |
Aviation Radiative Forcing
An important technical consideration for air travel is radiative forcing (RF) - non-CO₂ warming effects from aviation including contrail formation, cirrus cloud enhancement, and NOx chemistry. These effects may increase the effective warming impact of aviation by a factor of 2-4x compared to CO₂ alone. The GHG Protocol allows but does not require companies to apply an RF uplift factor. However, many leading reporters and frameworks (including some SBTi guidance) recommend applying an uplift of approximately 2x for air travel to reflect the full climate impact.
An employee flies London to New York (5,570 km) in business class. The emission factor for long-haul business class is 0.429 kgCO₂e/passenger-km. What are the Category 6 emissions for the outbound flight?
Why Business Class Emits More
Business class passengers occupy significantly more aircraft floor space per seat than economy class passengers. Since the aircraft's total fuel consumption is allocated by seat area (or seat count, depending on the method), business class passengers are allocated a larger share of total flight emissions. This is not merely a comfort premium - it reflects the physical reality of floor space consumed per passenger.
Reducing Category 6 Emissions
Common reduction strategies include:
- Virtual meeting policies: Substituting video conferencing for short-haul flights
- Train-first policies: Mandating rail over air for journeys under 4-6 hours
- Cabin class restrictions: Limiting business class to flights above a minimum duration (e.g., 6 hours)
- Offset programmes: Requiring employees to offset travel emissions (though this should supplement, not replace, reduction)
- Travel budgets expressed in CO₂e: Giving employees carbon budgets rather than solely cost budgets
Business travel fell sharply during the COVID-19 pandemic (2020-2021), causing many companies to report dramatically lower Category 6 emissions. As travel rebounded in 2022-2023, companies discovered that virtual alternatives had reduced (but not eliminated) the need for in-person meetings. Many companies now set Category 6 reduction targets based on 2019 (pre-pandemic) baselines rather than 2020-2021 anomalies, treating the pandemic period as a structural discontinuity requiring a base year restatement.
Key Takeaways
- 1Category 6 covers employee business travel in vehicles not owned by the company - flights, trains, taxis, rental cars, and hotel stays
- 2The distance-based method using passenger-km and mode-specific emission factors is the recommended calculation approach
- 3Business class flights emit roughly 3x more than economy class per passenger due to greater floor space per seat
- 4Radiative forcing from aviation (contrails, NOx effects) may multiply the effective warming impact of flights by 2-4x beyond CO2 alone
- 5Effective reduction strategies include virtual meeting policies, train-first mandates for short trips, and carbon budgets expressed in tCO2e rather than cost