The same carbon goes back to the air, within one lifetime.
Carbon goes round. A tree pulls carbon dioxide from the air and builds wood out of it. When the wood rots or burns, the same carbon goes back up. Round and round, within one lifetime. This cycle has run for millions of years, and the bath's level stayed roughly steady.
Age of the carbon in a log50 years
Age of the carbon in a lump of coal300,000,000 years
Coal, oil and gas are different. They are plants and sea life that were buried and pressed for hundreds of millions of years. Their carbon left the cycle long ago. When we dig it up and burn it, we add carbon the air has not seen since before the dinosaurs.
A wood, sixty years growing
↓→
It burns
A forest fire burns a wood that grew over 60 years. Where did that carbon come from?
From nowhere. Fire makes carbon.
Not yet. Fire makes nothing. It joins the carbon already in the wood to oxygen from the air. Every atom of carbon in the smoke was in the tree, and before that in the air.
From the ground. All burning adds new carbon.
Not yet. Burning coal adds carbon from the ground. Burning wood returns carbon that was in the air sixty years ago. The fire looks the same; the carbon's age is not.
From the air, over the last 60 years. It goes back where it came from.
Right. The trees built themselves out of the air. The fire returns it. The bath is back where it was before the wood grew; nothing was added from outside the cycle.
From burning coal, oil and gas since 18501,750 billion tonnes
From clearing forests since 1850750 billion tonnes
Since 1850 we have burned enough coal, oil and gas to send about 1,750 billion tonnes of carbon dioxide up. Clearing forests added about 750 more. Of all that, roughly 45 in 100 is still in the air. The rest went into the sea and into plants.
The world's emissions in one year, by where they come from. Tap the slice where most of the gas does NOT come from burning a fuel.
Tap the part of the picture that answers it.
One slice is mostly animals, soil and trees.
Electricity and heat34%
Factories and making things24%
Farming, forests and land22%
Transport15%
Buildings5%
Rounded, 2019.
Farming, forests and land
Right. Cows belch methane, fertiliser gives off other gases, and clearing forests releases carbon the trees held. About a fifth of the total, and most of it from no fuel at all.
Electricity and heat
Not yet. Nearly all of this is coal and gas burned in power stations. It is the biggest slice, and it is fuel from end to end.
Factories and making things
Not yet. Furnaces burn fuel, and making cement releases carbon out of the rock itself. But most of this slice is fuel.
Transport
Not yet. Almost entirely petrol, diesel and jet fuel. Nothing here comes from anywhere but a tank.
Buildings
Not yet. Gas boilers and stoves. Fuel again, burned at home.
United States14 tonnes a year
China8 tonnes a year
Europe6 tonnes a year
World average4.7 tonnes a year
India2 tonnes a year
Carbon dioxide per person, 2023, rounded.
How much a person adds depends mostly on how their country makes electricity, heats homes and moves about. An average American adds about 14 tonnes a year; an average Indian about 2. Most of that gap is coal, oil and gas burned on their behalf, not anything they do by hand.
Set how many people there are and how much each one adds. The drain stays at today's 22 billion tonnes.
Poured in each year2 billion tonnes
Drained out by oceans and plants22 billion tonnes
1 billion · 2 tonnes1 billion people at 2 tonnes each is 2 billion tonnes a year, under what the drain takes out.
Poured in each year5 billion tonnes
Drained out by oceans and plants22 billion tonnes
1 billion · 5 tonnes1 billion people at 5 tonnes each is 5 billion tonnes a year, under what the drain takes out.
Poured in each year8 billion tonnes
Drained out by oceans and plants22 billion tonnes
1 billion · 8 tonnes1 billion people at 8 tonnes each is 8 billion tonnes a year, under what the drain takes out.
Poured in each year14 billion tonnes
Drained out by oceans and plants22 billion tonnes
1 billion · 14 tonnes1 billion people at 14 tonnes each is 14 billion tonnes a year, under what the drain takes out.
Poured in each year4 billion tonnes
Drained out by oceans and plants22 billion tonnes
2 billion · 2 tonnes2 billion people at 2 tonnes each is 4 billion tonnes a year, under what the drain takes out.
Poured in each year10 billion tonnes
Drained out by oceans and plants22 billion tonnes
2 billion · 5 tonnes2 billion people at 5 tonnes each is 10 billion tonnes a year, under what the drain takes out.
Poured in each year16 billion tonnes
Drained out by oceans and plants22 billion tonnes
2 billion · 8 tonnes2 billion people at 8 tonnes each is 16 billion tonnes a year, under what the drain takes out.
Poured in each year28 billion tonnes
Drained out by oceans and plants22 billion tonnes
2 billion · 14 tonnes2 billion people at 14 tonnes each is 28 billion tonnes a year, over what the drain takes out.
Poured in each year8 billion tonnes
Drained out by oceans and plants22 billion tonnes
4 billion · 2 tonnes4 billion people at 2 tonnes each is 8 billion tonnes a year, under what the drain takes out.
Poured in each year20 billion tonnes
Drained out by oceans and plants22 billion tonnes
4 billion · 5 tonnes4 billion people at 5 tonnes each is 20 billion tonnes a year, under what the drain takes out.
Poured in each year32 billion tonnes
Drained out by oceans and plants22 billion tonnes
4 billion · 8 tonnes4 billion people at 8 tonnes each is 32 billion tonnes a year, over what the drain takes out.
Poured in each year56 billion tonnes
Drained out by oceans and plants22 billion tonnes
4 billion · 14 tonnes4 billion people at 14 tonnes each is 56 billion tonnes a year, over what the drain takes out.
Poured in each year16 billion tonnes
Drained out by oceans and plants22 billion tonnes
8 billion · 2 tonnes8 billion people at 2 tonnes each is 16 billion tonnes a year, under what the drain takes out.
Poured in each year40 billion tonnes
Drained out by oceans and plants22 billion tonnes
8 billion · 5 tonnes8 billion people at 5 tonnes each is 40 billion tonnes a year, over what the drain takes out.
Poured in each year64 billion tonnes
Drained out by oceans and plants22 billion tonnes
8 billion · 8 tonnes8 billion people at 8 tonnes each is 64 billion tonnes a year, over what the drain takes out.
Poured in each year112 billion tonnes
Drained out by oceans and plants22 billion tonnes
8 billion · 14 tonnes8 billion people at 14 tonnes each is 112 billion tonnes a year, over what the drain takes out.
The world has 8 billion people. For the total to come under what the drain takes out, what must the per-person number fall to?
Under 8 tonnes each, where China is now.
Not yet. 8 billion at 8 tonnes is 64 billion tonnes, nearly three times the drain. China's number is a long way above where the total comes under.
It cannot be done at 8 billion. The people are the problem.
Not yet. At 2 tonnes each, 8 billion people make 16, and the drain takes 22. The total is people times tonnes, and only one of those two has moved sevenfold between countries.
Under about 3 tonnes each, near where India is now.
Right. 8 billion at 2 tonnes is 16, under the drain. At 5 it is 40, about where the world is today. The number of people matters less than the tonnes behind each one.
Move both controls.
Of every 100 tonnes of carbon dioxide humans have added since 1850, how many came from the United States and Europe together?
Pick one. Nothing is scored.
United States25%
Europe17%
China15%
India3%
Everyone else40%
Share of all carbon dioxide added since 1850, rounded.
About 40.Most people guess from today's totals, where China leads. But the bath fills over centuries, and the US and Europe began burning coal a hundred years before most of the world. About 40 in every 100 tonnes up there today are theirs.
Which of these returns carbon that was already going round, and which adds carbon from the ground?
One card at a time. Tap the pile it belongs to.
Card 1 of 6
A gas boiler heats a house.
A farmer burns the straw left after harvest.
A jet burns kerosene.
Leaves rot on a forest floor.
A cement kiln heats limestone and the rock gives off carbon dioxide.
A cow belches methane after eating grass.
A gas boiler heats a house. → Added from the ground
Not yet. This adds carbon from the ground. Gas was locked in rock for millions of years, and burning it puts that carbon in the air for the first time.
A farmer burns the straw left after harvest. → Already going round
Not yet. This is carbon already going round. The straw took its carbon from the air this summer and gives it back.
A jet burns kerosene. → Added from the ground
Not yet. This adds carbon from the ground. Kerosene is made from oil, and oil is old carbon that left the round trip long ago.
Leaves rot on a forest floor. → Already going round
Not yet. This is carbon already going round. The leaves grew from the air's carbon this year, and rotting returns it.
A cement kiln heats limestone and the rock gives off carbon dioxide. → Added from the ground
Not yet. This adds carbon from the ground. The carbon dioxide comes out of the rock itself, where it was locked for ages.
A cow belches methane after eating grass. → Already going round
Not yet. This is carbon already going round. The grass took the carbon from the air, and the cow sends it back as methane, which warms strongly while it lasts.
Air→Plant→Back to the air within years
The round trip. Coal, oil and gas broke out of it long ago.Right. Straw, leaves and grass took their carbon from the air this year or last, and give it back. Gas, kerosene and limestone release carbon that was locked in rock for millions of years. The cow is round-carbon too, but methane catches heat far more strongly than carbon dioxide while it lasts, so it still warms.
Lesson complete
Burning a tree returns carbon the tree just took. Burning coal adds carbon buried for millions of years.