Clients rarely ask me for a carbon number directly. They ask whether the flight is worth it, whether the internal hop can be a train, and why one itinerary costs more than a near-identical one. This is the list I work through to answer those questions with something other than a hunch.
What we are actually measuring
The Greenhouse Gas Protocol is the framework most companies and most operators use to account for emissions, and it splits them into three categories. A trip touches all three.
- Scope 1: direct emissions from sources we own or control, such as a company vehicle or fuel burned on site.
- Scope 2: indirect emissions from purchased electricity, heat or steam, which in travel terms covers the rooms we book.
- Scope 3: everything else across the value chain, including suppliers, business travel, waste and the transport that gets a group from one stop to the next.
For most travel programmes Scope 3 is more than seventy per cent of the total, and it is also the hardest to measure, because the data sits with hotels, operators and airlines rather than with us.
The five steps we run on every booking
- Start with what we already have. Energy bills for our own office and the fuel and mileage records we control are the easiest numbers to trust, so they go in first.
- Use a published method rather than a spreadsheet of our own. The Greenhouse Gas Protocol publishes tools and guidance for each scope, which keeps two advisors from producing two different figures for the same trip.
- Prioritise the material categories. We do not attempt everything at once; flights, ground transport and hotel nights come first, because those are where a single decision moves the number most.
- Bring in a specialist when the data is messy. An outside reviewer tells us what to collect, which tool to use, and how to report the result without overstating it.
- Assign an owner internally. Finance, operations and procurement all touch travel data, and a trip measured by nobody is a trip that is never reduced.
What happens when a number is never taken
- Reporting rules tighten on a schedule, and a late start means catching up under pressure.
- Corporate clients and funders increasingly ask for the figure before they sign.
- Two operators quoting the same route can look identical until one of them can show the breakdown.
- Claims without evidence invite the greenwashing question in the first client review.
- Unmeasured legs hide waste: a fifth hotel change nobody can justify once it is on paper.
What a measured trip gives back
The first payoff is usually money rather than emissions. Fewer hotel changes mean fewer transfers, fewer late arrivals and less spent on ground handling, and those savings show up long before any target date. The second payoff is credibility: when a client asks how the number was built, we can answer with a method, a source and a date instead of an adjective.
Where to start this week
Pick one recurring trip pattern, pull the last twelve months of it, and calculate the three scopes for that pattern alone. One honest route beats a whole portfolio of estimates, and it gives you something to compare against the next booking you make.
Where the number actually comes from
Flights dominate the total, so we start there: routing, cabin, stopovers and a realistic load factor rather than the marketing figure. Ground transport comes next, then hotels, then the small items clients enjoy arguing about. We keep one file per trip with the assumptions written down, so next season's estimate becomes a comparison instead of an argument, and we show which single change would move the number most.
The file also records what we chose not to count, which is the part most estimates leave out.