JASON Digital Lab: Earth Systems: Global Carbon Cycle

The Carbon Cycle While some carbon is locked up in rocks and fossil fuels (coal and oil), most of it is constantly in flux. Plants convert carbon dioxide into carbohydrates through photosynthesis. This carbon may or may not travel up the food chain; sooner or later, it will decompose and be returned to the atmosphere.

Changing the carbon cycle?
Deforestation affects the global carbon cycle. Deforestion not only reduces the amount forestland to absorb carbon dioxide, by burning the forests it releases more carbon dioxide into the air. Scientists have recorded rising levels ol carbon dioxide in the atmosphere worldwide. Carbon dioxide is one of the many 'greenhouse gases' suspected of trapping heat in the lower atmosphere and contributing to a phenomenon called global warming.

Where does the carbon dioxide for photosynthesis come from? Dead and decaying plants and animals release CO₂, but so do living animals, through respiration. Humans and animals inhale oxygen and exhale carbon dioxide.

Without green plants, humans and animals could not survive, for the atmosphere would soon fill with carbon dioxide as all the oxygen was used up! And without animals, plants could not survive. If this balance, or equilibrium, is upset, then the system will change, with significant consequences for all life forms.

Now explore the dynamics of the carbon cycle!