processes that release
carbon into the atmosphere



processes that retain carbon and keep it from entering Earth’s atmosphere 

Carbon dioxide (CO2) is a gas in the atmosphere and is vital to life on Earth. Yet, too much carbon dioxide in the air can be harmful to the planet. What amount is just right? The amount that exists at any one time depends on the balance between carbon sources and carbon sinks.




burning fossil fuels

animal respiration,
such as breathing

storing of carbon by plants on land

storing of carbon
by plants in water

deep ocean

decomposition of animal waste
and dead animals and plants

formation of fossil fuels
(such as peat, coal, and oil)


Too Much Carbon

If more gases that contain carbon are released than can be absorbed, there will be excess carbon gases in the atmosphere. That affects how energy from the sun is absorbed and reflected on Earth. It is when fossil fuels, such as peat, change from carbon sinks to carbon sources that global temperatures increase and the climate begins to change.

The Role of Wetlands

Wetlands, like bogs, cover only a small part of the planet. Yet, their carbon-capturing abilities make a big difference. Wetlands also strain leaves and animal waste from the water. These things hold carbon, too. They become buried in sediment, locking even more carbon away.

Irish peat is extracted to be burned in power plants, creating more carbon dioxide emissions than coal.

This Irish bog formed over thousands of years.