2 atmosphere has about 1% the pressure of the Earth's at sea level. It is estimated that there is sufficient CO
2 ice in the regolith and the south polar cap to form a 30 to 60 kPa atmosphere if it is released by planetary warming. The Martian environment presents several terraforming challenges to overcome and the extent of terraforming may be limited by certain key environmental factors.
Terraforming Mars is still on theory since there are no "possible" ways to transport ammonia, hydrocarbons and fluorine compounds and since albedo is still very much present at Mars' surface and it lacks megnetosphere which can mitigate solar radiation and retaining the atmosphere