Carbon
Sources

processes that release carbon into the atmosphere

Carbon
Sinks

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? It depends on the balance between carbon sources and carbon sinks.

fires

volcanic eruptions

CARBON SOURCES (CO₂)

burning fossil fuels

animal respiration

storing of carbon by plants on land

storing of carbon by plants in water

deep ocean sediment

decomposition of animal waste and dead animals and plants

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

CARBON SINKS

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 on Earth. When peat is burned, it changes from a carbon sink to a carbon source and global temperatures can increase. Then the climate may become warmer.

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.