Whose count is it
- The ovenThe lightsThe flour lorryThe customers
Picture a bakery. The oven burns gas: that smoke comes out of the bakery's own chimney. The lights run on electricity made at a power station miles away. The flour came from a farm by lorry. Customers drive in. Which of those is the bakery's footprint? Somebody had to write the rule.
- Scope 1your own chimneyScope 2power you buyScope 3everyone else's
In 2001 a group called the Greenhouse Gas Protocol wrote the rule most companies now use. It sorts a footprint into three scopes. Scope 1: smoke from things you own, like the oven. Scope 2: the electricity you buy. Scope 3: everything else your business causes but does not own: the farm, the lorry, the customers' cars.
Three parts of the bakery's count. Tap the one that is scope 3.
Tap the part of the picture that answers it.
The gas ovenThe electricity billThe flour lorryThe flour lorry
Right. Scope 3. The bakery caused the journey by ordering flour, but the lorry is the haulier's, so its smoke is in the bakery's count only as scope 3.The gas oven
Not yet. Scope 1. The bakery owns the oven and the gas burns on its premises. That smoke is as direct as a footprint gets.The electricity bill
Not yet. Scope 2. The bakery did not make the power, but it bought it, and the rule gives bought electricity a scope of its own.- Scopes 1 and 20.14 in 100 of Heathrow's 2025 countScope 3: the planes95.6 in 100 of Heathrow's 2025 countScope 3: everything else4.3 in 100 of Heathrow's 2025 count
Now an airport, under the same rule. Heathrow's own count for 2025 is about 19.4 million tonnes. Its vehicles and boilers, plus the electricity it buys, are under 1 in 100 of that. The planes, which the airlines own, are 95.6 in 100 by its own chart. Scope 3 is 99 in 100. Same rule, opposite shape.
- Scopes 1 and 20.14 in 100The planes95.6 in 100
Heathrow stops burning gas in every building it owns. By roughly how much does its total count fall?
By less than 1 in 100.
Right. The buildings are scope 1, and scope 1 and 2 together are under 1 in 100 of the count. The planes fly on jet fuel, not on the terminal's boilers.To zero.
Not yet. Zero would mean the planes stopped. The airport's own gas is the smallest sliver of its count, so removing it barely moves the bar.By about half.
Not yet. Half of Heathrow's count would be nearly ten million tonnes of boiler gas. The buildings are nothing like that; the planes are the count. Set which scopes a count includes and which business is counting. The bakery's tonnes are made up; the airport's shares are Heathrow's own 2025 figures.
Counted20 tonnes, made upFull count100 tonnes, made upWhat the count includes: Scope 1 only · Which business: The bakery
Bakery, scope 1 only: the oven, 20 tonnes.
Counted0.14 in 100 of the full countFull count100 in 100 of the full countWhat the count includes: Scope 1 only · Which business: Heathrow
Heathrow, scope 1 only: its own vehicles and boilers. Under 1 in 100 of its full count.
Counted30 tonnes, made upFull count100 tonnes, made upWhat the count includes: Scopes 1 and 2 · Which business: The bakery
Bakery, scopes 1 and 2: the oven and the bought electricity, 30 tonnes.
Counted0.14 in 100 of the full countFull count100 in 100 of the full countWhat the count includes: Scopes 1 and 2 · Which business: Heathrow
Heathrow, scopes 1 and 2: add the electricity it buys, which Heathrow counts as almost nothing because it buys renewable power. Still under 1 in 100.
Counted100 tonnes, made upFull count100 tonnes, made upWhat the count includes: Scopes 1, 2 and 3 · Which business: The bakery
Bakery, all three: add the flour's farm, the lorries and the customers' cars. 100 tonnes.
Counted100 in 100 of the full countFull count100 in 100 of the full countWhat the count includes: Scopes 1, 2 and 3 · Which business: Heathrow
Heathrow, all three: add the planes and everything else. 100 in 100, about 19.4 million tonnes in 2025.
Which business could report a tiny footprint by counting scopes 1 and 2 only?
Neither. The rule makes all three compulsory.
Not yet. The 2001 rule did not: scope 3 was optional. Some newer rules require it, and the question of which rule a report follows is the first thing to ask of it.The airport. 99 in 100 of its count is scope 3.
Right. Under scopes 1 and 2 Heathrow's count is a sliver; under all three it is 19.4 million tonnes. The 2001 rule made scope 3 optional, which is why the question matters.The bakery. Its oven is small.
Not yet. The bakery's oven is a fifth of its count, and with its electricity, nearly a third. Leaving out scope 3 hides most of the bakery's count, but not nearly all of it.Move both controls.
- scope 1The airlinescope 3The airportscope 3The employer
So who owns a flight's smoke? The airline counts it as scope 1: its planes burn the fuel. Heathrow counts the same tonnes as scope 3. The passenger's employer counts the trip as scope 3 too. One tonne, three counts, each answering a different question. And an international flight's tonne sits outside every country's own total.
- The whole count19.4 million tonnesThe planes18.6 million tonnes
Heathrow's 2025 count was about 19.4 million tonnes. About 95.6 in 100 of it was the planes. Roughly how many million tonnes was that?
million tonnesTake 95.6 hundredths of 19.4.
Right. About 18.6 million tonnes, from aircraft the airport does not own. The sum is lesson 9's shape: a fuel burn modelled for each flight from radar timings near the airport, the straight-line distance to the destination and the aircraft type, times the UK's factor. - scope 1Own vansscope 3A courier's vans
A clothes shop reports its footprint fell 40 in 100. It closed its own delivery vans and hired a courier. The same parcels go down the same roads. What could make the number fall?
The courier counts them as scope 2.
Not yet. Scope 2 is bought electricity only. The courier's vans are the courier's scope 1, and the shop's scope 3.The vans moved from scope 1 to scope 3. A count of scopes 1 and 2 no longer sees them.
Right. The smoke is still on the road. It moved from the shop's own chimney, so to speak, to somebody else's, and a count that stops at scope 2 lost sight of it.Nothing. A courier's vans give off the same smoke.
Not yet. They do, which is the point. The smoke is the same and the count changed. A footprint is a count, and a count has edges.
Lesson complete
The same tonne can sit in three counts. Which scopes a count includes decides what it can hide.