Net Zero Airports? We Need to Talk About Facilitated Emissions

Airports are increasingly publishing impressive carbon-reduction claims.

“Airport emissions reduced by 50%.”

“Carbon-neutral operations.”

“Net zero airport.”

These statements may be technically correct within a narrowly defined reporting boundary. But they can also create a misleading impression for passengers if the overwhelming majority of emissions associated with using the airport—the fuel burned by aircraft—are excluded.

An airport may have genuinely reduced emissions from:

• terminal electricity;
• heating;
• airport-owned vehicles;
• refrigerants;
• lighting; and
• administrative operations.

These are worthwhile achievements.

But they are not the same as reducing the emissions from aviation activity facilitated by the airport.

The aircraft fuel problem

Aircraft fuel does not appear at an airport by accident.

It is transported to the airport, stored in dedicated fuel farms, managed by specialist operators and dispensed into aircraft through infrastructure located on airport land.

The airport may:

• own the fuel farm;
• lease it to a contractor;
• grant a fuel concession;
• charge fixed rent;
• receive throughput-related income;
• control access to the site;
• approve infrastructure expansion; or
• facilitate the sale and delivery of fuel to airlines.

Even where the airport does not legally own the fuel, it provides the infrastructure and permission needed for that fuel to be supplied.

Yet the subsequent combustion of the fuel may be almost entirely absent from the airport’s headline carbon footprint.

The airline records the fuel combustion as its Scope 1 emissions. The fuel supplier may report the combustion under Scope 3 Category 11, use of sold products. The airport may include only the energy used to operate the fuel farm or a limited estimate of aircraft activity close to the airport.

Each individual accounting decision may be technically defensible. Taken together, however, they can leave a major gap in what passengers understand an airport’s carbon claim to mean.

The limitations of the landing-and-take-off boundary

Airport carbon inventories commonly include aircraft emissions within the landing-and-take-off, or LTO, cycle.

The LTO cycle covers aircraft activity around the airport, including:

• taxiing;
• take-off;
• initial climb;
• approach; and
• landing.

The ICAO LTO methodology represents emissions in the vicinity of airports and generally covers aircraft activity below 3,000 feet.

This is useful for assessing local air quality and airport operations. It can also identify opportunities to reduce taxiing, holding and auxiliary power-unit use.

But it excludes most of the fuel used during a flight.

For a journey from Newcastle to Tenerife, the airport inventory may record taxiing, take-off and initial climb. It may exclude several hours of climb, cruise and descent, even though the entire journey began at the airport and depends on its infrastructure.

An LTO figure should therefore not be presented as though it represents the full climate impact of the flight.

The logical gap between the bus and the aircraft

There is also a striking inconsistency in how passenger travel is treated.

A passenger may buy a bus ticket to reach the airport. That journey can be included within the airport’s Scope 3 surface-access emissions.

The passenger then buys a plane ticket and flies from the same airport. Most of that flight may be excluded from the airport’s reported footprint.

Why should the two journeys be treated so differently?

The airport does not own the bus.

It does not control the bus fuel.

It may not sell the bus ticket.

Yet the bus journey is accepted as relevant because it occurs specifically to allow the passenger to use the airport.

The same logic applies even more strongly to the flight.

The aircraft journey is not incidental to the airport’s business model. It is the principal purpose of the airport.

The airport:

• provides the runway, terminal, stands and gates;
• promotes routes and destinations;
• charges airlines and passengers;
• benefits from increasing passenger numbers;
• provides or enables fuel infrastructure; and
• may seek planning approval for additional flights and capacity.

The GHG Protocol already recognises that customer travel to and from business facilities may be a relevant downstream emission. Its Category 9 guidance specifically identifies customer travel to retail facilities as a potentially significant source.

If customer travel to a site is relevant, the onward transport service that defines the purpose of that site cannot logically be dismissed as unrelated.

Introducing facilitated emissions

To address this gap, I propose a supplementary reporting category:

Facilitated emissions

Facilitated emissions are greenhouse gas emissions arising from activities undertaken by customers, tenants, concessionaires, transport operators or other third parties that are enabled by a business’s infrastructure, premises, permissions or commercial services.

The reporting business may not own or directly control the emitting source. It may not legally sell the fuel or transport service. But it provides an essential facility or commercial connection without which the activity could not occur in substantially the same form.

For an airport, facilitated emissions could include:

• the full emissions from departing flights;
• passenger travel to and from the airport;
• aviation fuel dispensed through airport infrastructure;
• concession-operated ground activities; and
• other material third-party transport enabled by the airport.

These emissions should be reported separately from the formal GHG Protocol Scope 1, Scope 2 and Scope 3 totals where necessary to avoid double counting.

But they should still be disclosed prominently.

A better airport carbon report

A transparent airport report should distinguish between four levels of emissions.

1. Airport-controlled emissions

These include:

• onsite fuel combustion;
• airport-owned vehicles;
• refrigerant leakage;
• purchased electricity;
• heating; and
• other emissions under the direct control of the airport operator.

2. Site-related Scope 3 emissions

These may include:

• staff commuting;
• contractors;
• waste;
• purchased goods and services;
• ground handlers; and
• passenger surface access.

Airport Carbon Accreditation already recognises Scope 3 sources such as aircraft, surface access and staff travel as relevant third-party airport emissions.

3. Aircraft LTO emissions

These include taxiing, take-off, approach and landing close to the airport.

They are useful but should be labelled clearly as only part of aircraft emissions.

4. Facilitated full-flight emissions

These should include the estimated total fuel combustion associated with departing flights from the airport.

The reporting boundary should be explained clearly—for example, whether it includes:

• departing flights only;
• full return journeys;
• domestic and international flights;
• cargo;
• private aviation; and
• non-CO₂ aviation effects.

What a fair claim should look like

Instead of saying:

“Airport emissions have fallen by 50%.”

An airport should say:

“The airport operator has reduced its Scope 1 and Scope 2 emissions by 50% from the stated baseline. These emissions exclude most emissions from aircraft flights. Full departing-flight emissions are reported separately as facilitated emissions.”

That does not diminish the airport’s achievement.

It makes the achievement understandable.

Airports are not the only example

The same issue applies to other transport and destination businesses.

Ports

A ferry or cruise terminal may reduce electricity and port-vehicle emissions while excluding most vessel fuel.

Facilitated emissions would include the full emissions of vessels using the port.

Bus and coach stations

A station may operate on renewable electricity while the buses and coaches using it continue to burn diesel.

The journeys are facilitated by the station’s infrastructure and commercial activity.

Rail stations

Station lighting and heating may be net zero while train traction energy remains outside the operator’s claim.

Freight terminals and logistics hubs

A terminal may report efficient cranes and warehouses while omitting the HGV, rail and shipping emissions generated by the freight movements it enables.

Stadiums and major venues

A stadium may have renewable electricity and low-carbon heating, but spectator travel can dominate the footprint of an event.

Shopping centres and retail parks

A centre may report building emissions while ignoring large volumes of customer and delivery traffic caused by its location and business model.

Digital booking platforms

Flight, hotel, freight and ride-hailing platforms may not own the aircraft, vehicles or buildings involved, but they actively facilitate and profit from the associated activity.

A practical test

Facilitated emissions should be reported where:

• the activity is integral to the business model;
• the business receives revenue or commercial benefit from it;
• the business provides essential infrastructure, access or intermediation;
• the business influences capacity, customer choice or operating conditions;
• the emissions are material;
• they can be reasonably estimated; and
• excluding them could mislead stakeholders about the organisation’s climate impact.

This does not mean every business should account for every possible consequence of its existence.

It means that a business should not claim to be net zero while excluding the dominant emissions arising from the principal activity it exists to enable.

Reporting outside the formal scopes

The GHG Protocol already requires some emissions to be disclosed separately from the formal scopes.

For example, direct biogenic CO₂ from burning biofuels is reported outside Scope 1 as a separate memorandum item, while methane and nitrous oxide remain within Scope 1.

This demonstrates that an emission does not need to fit neatly within Scope 1, Scope 2 or Scope 3 to require transparent disclosure.

Facilitated emissions could be presented in the same wider reporting section:

• formal Scope 1;
• formal Scope 2;
• formal Scope 3;
• biogenic CO₂ outside scopes;
• facilitated emissions;
• removals;
• avoided emissions; and
• offsets.

The important point is that facilitated emissions should not be hidden in a footnote.

The real question for airports

The question is not simply:

“Has the airport reduced the emissions it directly controls?”

It is:

“What proportion of the total climate impact associated with the airport is covered by its reduction or net-zero claim?”

An airport may have reduced its controlled emissions by 50% while full aircraft emissions remain unchanged or increase as passenger numbers grow.

Without clear boundaries, both statements can be true:

• the airport operator has substantially reduced its footprint; and
• the overall aviation activity facilitated by the airport has become more carbon intensive.

Passengers deserve to understand that distinction.

Airports, ports, stations and other transport hubs should report not only the emissions they own, but also the material emissions they facilitate.

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