How Carbon Moves Between Air and Living Things

What is the Carbon Cycle?

Carbon is an element found in all living things. It exists in the air as a gas called carbon dioxide (CO₂). Carbon moves between the atmosphere (the air around Earth) and living organisms in a continuous journey called the carbon cycle. This cycle has been happening for billions of years and is essential for life on Earth.

How Plants Pull Carbon from the Air

Plants are carbon's first stop on its journey. When plants photosynthesise, they take in carbon dioxide from the air through tiny holes in their leaves called stomata. They use sunlight, water, and this carbon dioxide to make food and grow. The carbon becomes part of the plant's leaves, stems, and roots.

How Carbon Moves to Animals

When animals eat plants, they consume the carbon stored inside them. A cow eating grass, a rabbit nibbling clover, or a human eating an apple—they're all taking in carbon. Animals use this carbon for energy and to build their bodies. When animals eat other animals, carbon passes along the food chain too.

Carbon Returns to the Atmosphere

Living things release carbon back into the air through respiration. This happens when animals and plants breathe out, breaking down food for energy and releasing carbon dioxide. When living things die, decomposers like bacteria and fungi break down their bodies, releasing carbon back to the soil and air. Even burning wood or fossil fuels releases carbon dioxide.

The Big Picture

The carbon cycle is perfectly balanced in nature—carbon released equals carbon absorbed. However, humans burning fossil fuels like coal and oil adds extra carbon dioxide to the atmosphere, disrupting this balance. Understanding the carbon cycle helps us see why this matters for our planet's future.

What is the Carbon Cycle?

Carbon is part of everything alive. It moves between the air and living things in a circle called the carbon cycle. This keeps happening over and over.

Plants Start the Journey

Plants pull carbon dioxide from the air. They use it to grow. The carbon becomes part of their leaves and stems. This is called photosynthesis.

Animals Eat the Carbon

When you eat an apple or lettuce, you eat the carbon inside the plant. Cows eat grass and get carbon too. The carbon becomes part of your body and gives you energy.

Carbon Goes Back to the Air

When you breathe out, you release carbon dioxide back into the air. Animals do this too. When plants and animals die, tiny creatures in the soil break them down. This releases carbon into the air again.

Why Does This Matter?

The carbon cycle has been balanced for millions of years. But now humans burn fossil fuels like coal and oil. This adds too much carbon dioxide to the air. This is changing our climate.

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