I got a lot out of your comment, but I don't know that Mars and Earth are directly comparable. - Earth has nearly 10x the surface area of Mars. This decreases

I got a lot out of your comment, but I don't know that Mars and Earth are directly comparable. - Earth has nearly 10x the surface area of Mars. This decreases the rate of escape. - Mars has lower gravity meaning escape velocity is roughly 1/3 Earth's, or escape energy is 1/10. This increases the rate of escape. - Mars has lower temperatures, which reduces what fraction of the atmosphere is at an escape velocity. This reduces the rate of escape. Though if we terraform it, maybe it warms up as well? So Mars and Earth are not easily compared, and are likely off by an order of magnitude. Still, it is worth thinking about what general scale we are talking about. Terraforming requires a civilization with access to resources many times our own.