Summary:
- Carbon is essential for life on Earth and, as carbon dioxide, it is an important atmospheric gas.
- Carbon occurs in many forms on Earth.
- The element moves through organisms and then returns to the environment.
- Healthy living forests and the oceans act as carbon sinks.
- Fossil fuels are a source for CO2 when they form, but they are a sink when they are used to supply our energy demands.
- The amount of CO2 in the atmosphere is very low.
- This means that a small increase or decrease in the atmospheric CO2 can have a large effect.