The Milankovitch cycles show the levels of CO2 and temperature decreasing and increasing naturally over time due to the Earths orbit. How would the Earth's orbit in any way lower levels of CO2?
It most likely would not directly affect CO2 levels.
Milankovitch cycles describes the collective effects of changes in the Earth's movements upon its climate. They are observations all related to the energy received by the sun due to different orbital positions and inclinations.
None of them directly affect CO2 concentrations, although water temperatures and plant proliferation may be enabling factors.