There is a fundamental problem with terraforming Mars; it has no magnetic field to keep the solar “winds” from blowing away the atmosphere. Humans will not be able to live outside on the surface of Mars, no matter how long we try to generate atmospheric oxygen without a planetary magnetosphere to divert the high speed ions escaping from the sun. At one point in the planet Mars’ life time it had an atmosphere and liquid water on the surface but now nothing that counts. The surface of Mars now has an atmospheric pressure of 0.0060 atm!
Perhaps we could generate a Martian artificial planetary magnetosphere, but I don’t know how.
In all honesty I think at that time scale it may be more practical to create a lifeform that does not depend on oxygen or water, and only needs sunlight for energy. It may have to be silicon based, and I use the word "lifeform" in a very liberal sense.
I thought it's more an issue of Mars not having enough magnetosphere to retain a decent atmosphere. Unless you're producing silly amounts of oxygen (outpacing loss due to solar wind etc.) it will never be viable.
On earth that was partly because the oceans absorbed a lot of oxygen. And then the rocks. Only once the water was saturated and the rocks had all oxidised did it start to build up in the atmosphere.
I feel like this is something you’d hear in 1500 about America.
“A forlorn land covered in crages and stormes, and wholly bereft of life giving aether, this continente of ‘Columbia’ is a kingdom moste unsuitable for a civilised Englishman.”
It had air, water, game, forest, and immediately arable land (cleared by people who had died in imported pandemics). It even had gravity. What does Mars have besides caustic dirt?
We have no valid reason to assume a pregnancy could be carried to term in Mars gravity.
Is there anyway we could do that in several orders of magnitude less on Mars?
Even 1 million times faster is still several human life-times.