Even if CO2 concentration in our atmosphere were 100%, ocean temperatures would still control the planet’s atmospheric temperature.
Since warming and cooling of the oceans always precedes warming and cooling of the atmosphere, this means that the oceans are controlling Earth’s temperatures, not the atmosphere. This means that CO2 does not warm or cool the planet in any significant amount, but instead only delays or moderates the temperature change effects that the oceans cause in the atmosphere.
CO2 retains some heat in the atmosphere as a temporary intermediate but in a relatively minor amount compared to water vapor. CO2’s effect is seen most at night in very dry areas such as deserts, and in the cold and dry air of the upper atmosphere and the polar regions, but it is a function of ocean temperature. CO2 causes a delay in warming and a delay in cooling, cycling after in correlation following ocean temperature, similar and co-dependent with water vapor.
Ocean temperatures are controlled by volcanic, tectonic and solar forces. El Ninos are a good example of the dominant control of ocean temperatures on atmospheric temperatures.
I have misplaced the source of the calculations in this table, but these are the correlations with average global temperature. Note that both ocean temperature and solar irradiation correlate with temperature better than CO2 and that ocean warming has a very high correlation. Global warming concerns about CO2 are a futile waste of resources.