Business travel carbon emissions: how to measure them

Sustainability reports, questionnaires from large clients and ESG programs increasingly ask for a figure many companies still cannot calculate: how much carbon their business trips emit. Measuring the carbon emissions of business travel does not require a lab, but it does require a method, reliable data and consistency from one year to the next.

At ArrowTur, which has managed corporate travel since 1989, we see that the hardest part is rarely the formula. The problem is usually the data: trips booked through different channels, flight segments with no fare class recorded, hotel stays paid through expense claims. This guide shows how to set up the measurement in a practical way.

Where travel fits in the emissions inventory

The GHG Protocol, the most widely used methodology for greenhouse gas inventories, places business travel in vehicles owned by third parties (planes, buses, taxis, rental cars) under Scope 3, category 6. Hotel stays may also be included in this category. Employees’ daily commute between home and work belongs to a different category and should not be mixed in.

In Brazil, the Brazilian GHG Protocol Program, coordinated by the Getulio Vargas Foundation (FGV), adapts this methodology to the local context and offers a spreadsheet calculation tool updated every year. For companies just getting started, it is a good place to begin.

The data you need to collect

The calculation is only as good as the data behind it. For each trip, ideally you should have:

• Air: origin, destination, connections, cabin class and number of passengers. With the airports you can work out the distance of each segment.
• Hotels: city or country and number of nights.
• Ground: type of transport (bus, rental car, taxi or ride-hailing app) and mileage or route.
• Organization: traveler, department and cost center, so you know where the emissions come from.

When trips are booked through a travel agency, most of this information is already in the bookings. What falls outside, such as taxis paid by the traveler, can be estimated from expense claims.

How the calculation works, step by step

The basic logic is to multiply the activity by an emission factor. For air travel, the activity is the distance traveled per passenger (passenger-kilometer); for hotels, the number of nights; for cars, the kilometers driven or the fuel used.

Air travel

Calculate the distance of each segment between airports, including connections. Then apply the emission factor for the type of flight (domestic, short haul or long haul) and the cabin class. Methodologies assign more emissions to seats that take up more space, which is why business class weighs more than economy on the same flight.

Hotel stays

Multiply the number of nights by a factor per room per night, which varies by country because it depends on the local energy mix.

Ground transport

For rental cars and taxis, use mileage or fuel. For buses, the distance per passenger. If mileage is not available, estimate it from the route between the addresses.

Emission factors: pick a source and stick with it

Emission factors are published by recognized sources. Besides the Brazilian GHG Protocol Program tool, a widely used reference for travel is the annual table of UK government conversion factors, with values by flight type, cabin class and hotel stays by country.

Two precautions make a difference:

• Consistency: use the same source and version for the whole year and record which one you used. Switching sources halfway creates swings that do not reflect real changes.
• Non-CO2 effects of aviation: some tables offer factors with and without the additional effect of emissions at altitude. Decide which option to use, state it in the report and keep it.

From a number to a report

An annual total is useful for the inventory, but it does little to help reduce emissions. To become a management tool, the report should show:

• Emissions by department, cost center and traveler.
• The routes with the highest emissions and how many trips were made on them.
• The share of each category: air, hotels and ground transport.
• Relative indicators, such as emissions per trip or per employee, which let you compare periods even when travel volume changes.

With this picture, it is easier to set targets and track results month by month, just as you track spending.

Common measurement mistakes

• Counting only air travel: hotels and ground transport also count and can be significant on long trips or stays with many nights.
• Forgetting connections: a flight with a stopover covers a longer distance and has more takeoffs and landings than a direct flight.
• Ignoring trips booked outside the official channel: bookings made directly by travelers disappear from the report unless they are captured through expense claims.
• Including canceled trips: count only what was actually flown and used.
• Not documenting the method: without a record of sources and assumptions, the figure will not hold up in an audit or when a client asks.

Measuring business travel emissions with ArrowTur

ArrowTur provides its corporate travel clients with carbon emission reports calculated from the trips actually taken, considering segments, distances and cabin class, organized by traveler and cost center. Along with them, we send the tree replanting report we produce for every client. Because bookings go through a single channel, the data is more complete and the report is ready to feed your inventory and ESG report.

To learn more about the reports, contact our sales team at +55 11 5189-4120, on WhatsApp or through our Contact us page. We are available Monday to Friday, 7 a.m. to 7 p.m. (Brasília time), with an emergency on-call service outside these hours.

Read also: Sustainable corporate travel: how to cut emissions.

Frequently asked questions

Which inventory scope does business travel fall under?

Scope 3, category 6 (business travel), according to the GHG Protocol. Hotel stays can be included in the same category.

Do I need software to measure travel emissions?

Not necessarily. With organized data and a source of emission factors, a spreadsheet will do. The critical point is having complete data for every trip.

How often should I measure?

The inventory is usually annual, but tracking month by month helps you correct course before the year closes.