Comparison of Type I evolutions with different initial fractions of CO₂ in the atmosphere (black = 0%; orange = 25%; blue = 50%). The top panel shows that changing the initial atmospheric abundance by 50% only results in a 7% change in CO₂ partial pressure at 4.5 Gyr. The middle and bottom panels show that atmospheric water mass and magnetic moment are negigibly impacted by the initial CO₂ partitioning.