Where is CO2 found in nature?
Carbon dioxide is a minor, but very important, constituent of our atmosphere. It is present (2006) at about 381 parts per million (ppm) and has been rising at about 2 ppm/yr over the past 30 years. That is about one part in 2625. Green plants remove CO2 from the air and use it in a process called photosynthesis to produce sugars. (Plants also combine sugar molecules to make starches and cellulose).
