What happened when there was not enough carbon dioxide in the atmosphere to trap the sun's heat about 600 mya?

Decreased Temperatures

Explanation:

Because carbon dioxide traps heat in the atmosphere, a lessening of atmospheric carbon dioxide concentrations would mean that more heat could escape into space. This would result in a net decrease in the Earth's average temperature, assuming other factors remain the same.

Global temperature rise, warming oceans, shrinking ice sheets, and glacial retreat.