Net zero is on every company's website. Net means after a subtraction. Net zero is what you give off, minus what you take back out of the air, coming to nothing. Picture a company that gives off 100 tonnes and takes 100 tonnes back out. Net: zero. The sum is honest if both numbers are.
1990100 net emissions, 1990 = 100
The 2008 law, 205020 net emissions, 1990 = 100
The 2019 law, 20500 net emissions, 1990 = 100
The UK wrote it into law on 27 June 2019. By 2050 the country's net emissions must be 100 in 100 below 1990. The older law said 80 in 100. Net is the word doing the work: some tonnes may still be given off in 2050, if the same number are taken back out.
Given off100 tonnes
Taken out10 tonnes
A company gives off 100 tonnes and plants trees that take in 10. What is its net?
90 tonnes.
Right. A hundred out, ten back: ninety left in the air. Net is a subtraction, and the trees took back a tenth of the tonnes.
Zero. It planted trees.
Not yet. Planting is not the same as taking out a hundred tonnes. The trees took in ten. The other ninety are still in the air.
110 tonnes.
Not yet. The trees take carbon out of the air, not into it. Taking out is subtracted, not added.
You give off 100→You pay for 100 credits elsewhere→You subtract them→Net 0, on paper
A company can pay somebody else for the taking out, and subtract it. That is an offset: a credit for a tonne kept out of the air somewhere else. A forest kept standing, say. The subtraction is only true if the tonne really was kept out, and would not have been anyway. That second part is the trouble.
Picture a company giving off 100 tonnes and buying 100 forest credits. Move how many of those credits stand for a tonne that was really kept out of the air.
Given off100 tonnes
Really kept out100 tonnes
True net0 tonnes
Credits that were real, out of 100: 100
All 100 real. A hundred tonnes out, a hundred kept out elsewhere. Net zero, and true.
Given off100 tonnes
Really kept out50 tonnes
True net50 tonnes
Credits that were real, out of 100: 50
50 real. The company reports net zero. The air has 50 more tonnes in it than the report says.
Given off100 tonnes
Really kept out10 tonnes
True net90 tonnes
Credits that were real, out of 100: 10
10 real. The company reports net zero. The air has 90 more tonnes in it than the report says.
Given off100 tonnes
Really kept out0 tonnes
True net100 tonnes
Credits that were real, out of 100: 0
None real. The forest was never going to be cut. The company reports net zero and the air has all 100 tonnes.
When only 10 of the 100 credits are real, what is the company's true net?
Zero. It paid for 100.
Not yet. Paying is not taking out. The company bought a hundred pieces of paper; ten of them stood for a tonne kept out of the air.
90 tonnes, reported as zero.
Right. The ten real credits count. The ninety that were not are a subtraction on paper only. The report says zero and the air says ninety.
100. Offsets never count.
Not yet. The ten real ones do count, which is why the idea survives. The problem is the ninety, not the subtraction itself.
Move the control.
8 of 29
of 29 projects where the satellite studies found forest really saved
In January 2023 three newsrooms took scientists' satellite studies of rainforest projects sold through Verra, a big offset registry. In 29 projects the studies could measure, forest was really saved in 8. About 94 in 100 of those projects' credits, the newsrooms said, should never have been issued. Verra called the analysis unreliable. Later that year it changed its method.
Slide the marker to the share of the 29 projects' credits that the investigation said should not have been issued.
Slide the marker to where you think the answer is, then press Lock. Nothing is scored.
123
your guess · 0%
the answer · 94%
0%50%100%
1None0%
2Half50%
3All100%
Your guess: —
About 94 in 100, by the investigation's count. Guesses land near the middle, because a market that big feels as if most of it must be real. The forests in most of the projects were never going to be cut, so the credits subtracted tonnes that were never going into the air.
Cut at least 90 in 100 yourself
++
Remove the rest
++
EU, Sept 2026no offset-based neutral claims
So a rule grew around the subtraction. The 2021 standard big companies sign up to says: cut at least 90 in 100 of your own tonnes first, for most kinds of company; bought credits do not count as cuts; removals are for what is left. From September 2026 the EU bans calling a product climate neutral on offsets alone.
Each card is something a company does. Under the 2021 standard, does it count as a cut in its own tonnes, or not?
One card at a time. Tap the pile it belongs to.
Card 1 of 6
Halving the gas its factory burns
Buying forest credits to cover the factory's gas
Switching its vans to electric
Paying for a wind farm abroad and subtracting its tonnes
Closing its own plant and importing the product instead
A machine that pulls carbon out of the air and stores it underground, for the last 10 in 100
Halving the gas its factory burns → A cut
Not yet. A cut. Fewer tonnes come out of the company's own chimney. That is the quantity half of lesson 9's sum, and it is the company's own.
Buying forest credits to cover the factory's gas → Not a cut
Not yet. Not a cut. The chimney gives off what it gave off. The standard says bought credits do not count toward the cut, only toward what is left after it.
Switching its vans to electric → A cut
Not yet. A cut. The factor half of the sum: the same deliveries, far fewer tonnes from each kilometre, and the vans are its own.
Paying for a wind farm abroad and subtracting its tonnes → Not a cut
Not yet. Not a cut. The wind farm's tonnes are not the company's. The standard keeps cuts and credits in separate columns.
Closing its own plant and importing the product instead → Not a cut
Not yet. Not a cut. Lesson 10: the tonnes moved from scope 1 to scope 3. The product is still made, the smoke still rises, and the count just stopped seeing it.
A machine that pulls carbon out of the air and stores it underground, for the last 10 in 100 → Not a cut
Not yet. Not a cut; a removal. The standard keeps removals for the tonnes left after the 90 in 100 cut. It is real, and it is in the other column.
2A cut
vsvs
4Not a cut
Right. Two cuts, four not. A cut is fewer tonnes from your own sources. Everything else, including real removals, sits in a second column, and the standard says which column comes first.
The exhaust9 tonnes, say
vsvs
A forest creditbought
An airline calls a flight carbon neutral because it bought a forest credit for every seat. What has the plane's exhaust done?
Nothing different. The subtraction is on paper, and only as real as the credits.
Right. The tonnes stay in the air for centuries. A Dutch court said as much about KLM's claims in March 2024, finding 15 of 19 of them misleading; in Austria a court had found a CO2-neutral flight ad misleading the year before.
Been halved.
Not yet. Nothing in the sky changed by any amount. Halved is a number nobody counted. The exhaust is what it was; the claim is what moved.
Been cancelled out by the forest.
Not yet. The forest was standing before the flight. Cancelling needs a tonne taken out that would not otherwise have been, and most of the forest credits the 2023 investigation examined were not that.
Lesson complete
Net means after a subtraction. The subtraction is only as real as the tonnes taken out.