0
$\begingroup$

If CO2 only makes up about 0.04% of the earth’s atmosphere how do trees and organisms in the ocean produce oxygen to 10% of the earth’s atmosphere?

$\endgroup$
2
  • 1
    $\begingroup$ Short answer: They had a very long head start $\endgroup$ Commented Jun 29, 2018 at 6:26
  • $\begingroup$ Some places the atmospheric Oxygen is nearly 20 %. $\endgroup$ Commented Jun 29, 2018 at 18:38

1 Answer 1

1
$\begingroup$

A very long head start

To elaborate on Drake Johnson’s comment, CO2 used to be much higher in concentration. During the Great Oxygenation event, when cyanobacteria (ancestors) began photosynthesizing, they converted much of the CO2 into O2, driving CO2 concentrations down as they drove O2 up.

$\endgroup$
1
  • $\begingroup$ When was this and what temperature was the atmosphere in then? Good sources? $\endgroup$ Commented Jan 6, 2020 at 15:53

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .