The carbon cycle — Earth science, 14–17 years
How carbon moves between the air, living things, rocks, oceans and soil. Earth science, 14–17 years.
Carbon is always moving
Carbon atoms do not disappear when a leaf falls, an animal breathes or wood burns. They move between the atmosphere, living things, soil, oceans and rocks, sometimes quickly and sometimes over millions of years. This repeated movement is the carbon cycle.
Why follow the carbon?
Scientists needed a way to explain why carbon dioxide in the air can change while Earth still contains roughly the same atoms. The cycle links life, climate and rocks, and shows that a change in one store can affect the others. Burning fossil fuels matters because it moves ancient carbon into the atmosphere quickly.
A carbon atom’s journey
Imagine one carbon atom in atmospheric carbon dioxide. First, a tree takes it in during photosynthesis and builds it into wood. Next, the wood is eaten or decomposes, returning the atom to soil or air. If buried and changed for millions of years, it could become fossil fuel; burning it sends it back to the air.
The common mix-up
A reasonable mistake is to think that planting one tree cancels one unit of carbon dioxide forever. A growing tree stores carbon, but leaves, roots and wood eventually decompose or burn, and much of that carbon returns to the air. Trees can slow the movement of carbon, but storage is not automatically permanent.
Why it matters outside school
The carbon cycle helps people compare forests, soils, oceans and fossil fuels as carbon stores. It is used when estimating emissions, planning reforestation or judging whether a climate solution lasts. It also explains why protecting peatlands and old forests can matter: they may hold carbon that would otherwise reach the atmosphere.
Keep exploring
Other languages
Loading MyLeoNes™…