Why is it necessary for earth atmosphere to have carbon dioxide?

Answer 1

The earth's atmosphere contains a small amount of carbon dioxide because of the amount of plants and bacteria which photosynthesise. The atmosphere used to be mainly carbon dioxiide until bacteria first evolved. When the bacteria evolved it photosynthesised, producing oxygen and taking in carbon dioxide, make the composition of the atmosphere change. Furthermore, the carbon dioxide dissolves in oceans, is used to form sedimentary rocks and animals and shells are carbon based. Fossil fuels are also carbon based. All of this uses up the carbon dioxide, so there is only a small amount in the atmosphere.

Answer 2

The relative amount of CO2 in the atmosphere is low (~0.04%) because plants and some algae use CO2 to create their "food" source via photosynthesis:

6CO2 + 6H2O *= C6H12O6 + 6O2

*=photons of light.

Vast amounts of CO2 are consumed in this way in order to provide almost every living organism on earth with the O2 needed for aerobic respiration.

But Earth's atmosphere did begin with CO2 being the main gas.

Answer 3

because of deforestation, the number of oxygen in the atmosphere decreases, and thus, there is lots of carbon dioxide in the atmosphere. Currently the levels of carbon dioxide are about 0.039%.

Answer 4

CO2 used to comprise a much larger percent of our atmosphere, just as it does on Venus and Mars. Marine photosynthetic organisms found an advantage in breaking the CO2 into carbon they could use, releasing the O2 back into the atmosphere.

Answer 5

A mere fraction of a percent (0.028%) has kept the earth warm enough for life for millions of years. Now levels have risen to 400 ppm (parts per million) or 0.04%, a rise of 0.012%, almost half as much as the comfortable levels. This is what is causing global warming.

Answer 6

Yes because trees breath it and in return they give us oxygen.