Why has the carbon dioxide content of the early atmosphere decreased?

Answer 1

Because plants evolved and converted all the carbon dioxide into oxygen.
It was only recently that people started deforestation that carbon dioxide is present in the atmosphere in larger quantities.

Have a read of the article below. It gives a brief history of the earth's atmosphere

Answer 2

The carbon dioxide was converted to carbon by plants. This carbon was kept out of the way in coal, oil and gas deposits.

Answer 3

The evolution of green plants play the most important role in the process of reduction of CO2 (u know photosynthesis and stuff). But there are other reasons too.
One being the chemical reactions leading to the formation of the immense limestone deposites around the world.

Answer 4

Actually, it hasn't!! The earth, along with humans and plants, etc.. recycles all (on a molecular level). Meaning the amount of oxygen present before is the same amount as of today. I know it sounds impossible, however it is correct. I know many will say , but there are less plants, there are more people, etc.. however i did not say ALL molecules and atoms recycle into the same exact thing.

Energy of any type never dies, it transfers from one form to the next...

not too sure about all of that?? Please see Energy Conservation laws (yes, law, not theory).

Answer 5

evolution of green plants

Answer 6

zPlants