Corporate travel supplier questionnaire: climate data, targets and methodology

More than 30,000 hotels calculate their carbon footprint per occupied room with the same free method, the Hotel Carbon Measurement Initiative (HCMI). Ask a hotel for that figure and you can compare it with the next hotel on your list. Ask it to describe its sustainability program and you'll get a brochure.

A useful supplier questionnaire asks for figures, the method behind them and what they include, in a form you can compare side by side. This guide gives you the questions to send hotels, airlines and your booking platform, and what a useful answer looks like.

Why travel buyers are asking now

Hotel stays have been optional in business travel reporting. The GHG Protocol's guidance on business travel says companies "may optionally include emissions from business travelers staying in hotels," so many companies count flights and leave hotels out. The same guidance lists working with airlines and hotels to get emissions data as one way to collect it.

California is moving toward requiring travel emissions from large companies. At a July 2026 workshop, the California Air Resources Board proposed that companies covered by its climate disclosure law report five Scope 3 categories from 2027, business travel among them. The law covers companies with more than $1 billion in annual revenue that do business in California. The rules are still a proposal.

Our guide to collecting travel emissions data covers the reporting side. This one covers what to ask the companies you buy travel from.

Every answer needs a number, a method and a boundary

Whichever supplier you're writing to, ask for the same three things:

• A figure per unit you buy. Per occupied room night for a hotel, per passenger for a flight. A company-wide total tells you nothing about your own stays.
• The method, by name. HCMI for hotels, or the GHG Protocol, plus the source and year of any emission factors.
• The boundary. What's counted, what's left out, and which year the data covers.

Also ask whether anyone independent checked the figures. An unchecked number can still be useful, as long as you know it hasn't been checked.

Questions for hotels

1. What is your carbon footprint per occupied room night, and for which year?
2. Which method did you use to calculate it?
3. Does the figure include outsourced laundry and refrigerant leaks? HCMI counts both.
4. What share of your energy is renewable, and does it come from your own panels, a supply contract or certificates?
5. If we hold meetings with you, what is the footprint per square meter of meeting space per hour? HCMI calculates this too.
6. Do you take part in the Cornell Hotel Sustainability Benchmarking Index?

The renewable question has three possible answers. Panels on the roof produce power at the hotel. A supply contract or certificates pay for renewable power produced somewhere else, and the two are not the same thing.

The Cornell index publishes carbon, energy and water benchmarks by city and hotel type, so you can see whether a hotel's figure is high or low for where it is. The 2024 edition published benchmarks for 20,301 hotels in 83 countries, using 2022 data.

Questions for airlines

1. What were the emissions per passenger on the flights we took?
2. Which method and emission factors did you use, and from which year?
3. Did you apply a multiplier for the extra warming effect of emissions at altitude, known as radiative forcing? If so, which factor?

The GHG Protocol lets companies apply that multiplier, as long as they disclose the factor. Ask every airline for the same treatment, or one airline will look cleaner than another only because it left the multiplier out.

Questions for your travel agency or booking platform

Most of your data will come from here rather than from each supplier, so this is the list to get right.

1. Can you export hotel nights by property and city, and flights by route and cabin, for each traveler and cost center?
2. For hotels, do you use each hotel's own figure where one exists, or one average for every hotel?
3. Which emission factors do you use, from which source and year?
4. Do you apply radiative forcing, and at what factor?
5. Can you send the same data every quarter in the same format?

The second answer matters most. If your platform uses one average for every hotel, choosing a hotel with a lower footprint won't show up in your numbers at all. Our guide to calculating business travel emissions shows where hotel-specific figures fit.

Questions about targets

A supplier's target only helps you if it covers what you buy. Ask:

• What is the target, what is the base year, and what is the deadline?
• Has an outside body validated it?
• For a hotel company, does it cover franchised hotels as well as the ones it manages?
• How much have emissions changed since the base year?

The last answer is the most useful. Progress so far tells you more than a date decades away.

Keep it short enough to answer

Only ask what you'll use. In Europe, smaller suppliers can now say no to the rest: under the EU's 2026 changes to its sustainability reporting rules (Directive 2026/470), companies with 1,000 employees or fewer can decline requests that go beyond a voluntary reporting standard.

The lists above come to 18 questions. Send every hotel the first four, save the rest for your largest suppliers, and ask for answers in a spreadsheet so you can compare them.

When the answers come back, sort them like this:

Put the answers to work

Answers only help if they change your numbers or your choices. Four ways to use them:

1. Replace averages for your busiest hotels. Rank hotels by the nights your team spent in each last year. For the ones at the top, use the hotel's own figure per occupied room night in place of an average. The GHG Protocol calculation stays the same: nights multiplied by the figure per night.
2. Check each figure against its city. A hotel's footprint means little on its own. Compare it with the Cornell benchmark for the same city and type of hotel.
3. Keep a record of who answered. A supplier that doesn't answer tells you something too, and next year you'll want to know who you're still waiting on.
4. Ask again each year. Send the questions when you review your preferred hotels, so you can compare each answer with last year's.

Hotels with a lower figure for the same city and standard are worth adding to your preferred list. That's where a questionnaire starts to cut emissions rather than only count them.