Who gives off the most carbon dioxide? Count the tonnes from fuel and cement in 2023 and China is first by a long way: about 12.2 billion tonnes. The United States is second at 4.9, India third at 3.1. That is the total, and it is one true answer.
United States14.3 tonnes a person, 2023
China8.6 tonnes a person, 2023
World4.7 tonnes a person, 2023
United Kingdom4.5 tonnes a person, 2023
India2.1 tonnes a person, 2023
Now divide each by its people. The same 2023 tonnes come out as about 14.3 for each American, 8.6 for each Chinese person, 4.5 for each Briton, 2.1 for each Indian. The world average is 4.7. The order flips. Both lists are true, from the same tonnes. Per head is the second answer.
In total?
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Per head?
Which country is first in total, and which is first per head?
The United States at both.
Not yet. In total the United States is second, at less than half of China's tonnes. The per-head list is the one it tops.
China in total; the United States per head.
Right. China has four times the people. Its total is biggest and its per-head figure is a little over half the American one. Both are first at something.
China at both.
Not yet. Per head, China is below the United States, Canada and Australia. Dividing by 1.4 billion people brings its figure down to 8.6.
Set a country's people and its tonnes per head, and read the total. The total is one multiplied by the other; nothing else is in it.
Per head, tonnes2
Total, million tonnes200
People, millions: 100 · Tonnes per head: 2
100 million people at 2 tonnes each is 200 million tonnes a year.
Per head, tonnes5
Total, million tonnes500
People, millions: 100 · Tonnes per head: 5
100 million people at 5 tonnes each is 500 million tonnes a year.
Per head, tonnes14
Total, million tonnes1,400
People, millions: 100 · Tonnes per head: 14
100 million people at 14 tonnes each is 1,400 million tonnes a year.
Per head, tonnes2
Total, million tonnes700
People, millions: 350 · Tonnes per head: 2
350 million people at 2 tonnes each is 700 million tonnes a year.
Per head, tonnes5
Total, million tonnes1,750
People, millions: 350 · Tonnes per head: 5
350 million people at 5 tonnes each is 1,750 million tonnes a year.
Per head, tonnes14
Total, million tonnes4,900
People, millions: 350 · Tonnes per head: 14
350 million people at 14 tonnes each is 4,900 million tonnes a year.
Per head, tonnes2
Total, million tonnes2,800
People, millions: 1,400 · Tonnes per head: 2
1,400 million people at 2 tonnes each is 2,800 million tonnes a year.
Per head, tonnes5
Total, million tonnes7,000
People, millions: 1,400 · Tonnes per head: 5
1,400 million people at 5 tonnes each is 7,000 million tonnes a year.
Per head, tonnes14
Total, million tonnes19,600
People, millions: 1,400 · Tonnes per head: 14
1,400 million people at 14 tonnes each is 19,600 million tonnes a year.
Which pairing gives the biggest total?
The highest per head, whoever has it.
Not yet. Fourteen each for 100 million people is 1,400 million tonnes. Two each for 1,400 million people is 2,800. The small rich country's total is the smaller one.
1,400 million people at 14 each. Both halves matter.
Right. The total is people times per head. The most people at the highest rate is 19,600 million tonnes; no other frame comes close, and no real country is there.
The most people, whoever they are.
Not yet. 1,400 million at 2 each is 2,800 million tonnes. 350 million at 14 is 4,900. A smaller country at a high rate out-totals a bigger one at a low rate.
Move both controls.
2 shares eachHalf full
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1 share eachFull
There is a third kind of per. A plane's smoke divided by its passengers: the per-head figure of a half-empty plane is double a full one's, from the same fuel. A country's tonnes per pound of output, a steelworks' tonnes per tonne of steel. Every per is a choice of what to divide by, and the honest count says which.
100 passengers200 kg each
200 passengers100 kg each
A flight gives off 20 tonnes. With 100 passengers, that is 200 kg each. The same flight with 200 passengers: how many kilograms each?
kg
Right. A hundred kilograms each. The plane burned the same fuel and gave off the same 20 tonnes. The per-passenger figure halved because the divisor doubled. Nothing in the sky changed.
Each card is a true claim about carbon. What is it per: in total, per head, or per passenger?
One card at a time. Tap the pile it belongs to.
Card 1 of 6
China gives off more than any other country
An American gives off about three times what a Briton does
India's count is about a quarter of China's
A full plane halves each passenger's share
The world average is about 4.7 tonnes each
A long-haul economy seat is about 69 grams a kilometre
China gives off more than any other country → In total
Not yet. In total. It is a claim about all of China's tonnes added up. Per head, China is not first.
An American gives off about three times what a Briton does → Per head
Not yet. Per head. 14.3 against 4.5, each country's tonnes divided by its people.
India's count is about a quarter of China's → In total
Not yet. In total. 3.1 billion against 12.2. Per head the gap is the other way round from what you might guess: India is at 2.1, China at 8.6.
A full plane halves each passenger's share → Per passenger
Not yet. Per passenger. The plane's smoke is fixed; the divisor doubled.
The world average is about 4.7 tonnes each → Per head
Not yet. Per head. The world's 38 billion tonnes divided by its 8 billion people.
A long-haul economy seat is about 69 grams a kilometre → Per passenger
Not yet. Per passenger, and per kilometre too. The plane's fuel divided by its seats and by the distance.
2In total
++
2Per head
++
2Per passenger
Right. Two of each. Every claim is true, and none of them says the same thing as its neighbour. The number is only readable once you know what it was divided by.
Made inside the UK, 2024373 million tonnes
Bought by Britons, 2023699 million tonnes
One more divide, by borders. Counted inside the UK's borders, 2024: about 373 million tonnes. Counted by what Britons buy, wherever in the world it was made, 2023: about 699 million, roughly 10 tonnes a person. Same country, two borders drawn. The first is the one the law counts.
In totalthird
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Per headbelow average
A headline: India is now the world's third-biggest polluter. Per head, India is below the world average. Which is true?
The headline is wrong.
Not yet. In total, India's 3.1 billion tonnes is third after China and the United States. The headline is a true sentence that picked one per.
Per head is the only fair count, so the headline is unfair.
Not yet. Which per is fair is an argument, not a count. The count gives both numbers; the argument about which matters is yours to have, with both in view.
Both. Third in total, below average per head.
Right. Two true readings of one set of tonnes. The headline chose the total; a different paper could choose per head. Neither is wrong, and each leaves the other out.
Lesson complete
A total and a per-head figure are both true and rank countries differently. Every 'per' is a choice.