Carbon dioxide (CO₂)

A colorless, odorless, non-combustible gas, present in low concentrations in the air we breathe (about three hundredths of one percent by volume).

Carbon dioxide is produced when any substance containing carbon is burned. It is also a product of breathing and fermentation. Plants absorb carbon dioxide through photosynthesis.

Source: The Pacific Forest Trust Glossary 

Although it is released by human activities through the combustion of fossil fuels, it is also formed by certain natural processes (see carbon cycle).

Carbon dioxide is the principal greenhouse gas that contributes to global warming.

Source: GreenFacts

Carbon monoxide (CO) - Environmental cycles - Fossil fuel(s) - Greenhouse gas

GreenFacts Summary on Climate Change 2007 Update:

• 1. What makes the climate change?

Español: Dióxido de Carbono (CO₂)
Français: Dioxyde de carbone (CO₂)
Nederlands: Koolstofdioxide (CO2)

Climate Change

Arctic Climate Change

Forests

Desertification

Ecosystem Change