Is it possible to terraform mars, if we could what would we have to do?
Terraforming mars would be exceedingly difficult. The three variables that would need to be improved are the oxygen/CO2 content of the atmosphere, the average temperatures and the crucially the pressure of the atmosphere. You must however remember that it is not the % content of the air of both that matters, but the partial pressure of these gases. As the pressure on mars is a lot lower even if the atmosphere was 100% oxygen it would still be impossible to breath. Of these the easiest to change would be the CO2 and oxygen content of the air, as you could simply set up heated greenhouses to convert one to the other, however this would in turn lower the temperature of the planet, as you would be creating a negative greenhouse effect, as you pull all this CO2 out of the atmosphere. Temperature would be much more difficult. The lowest temperatures found on mars are in the order of -140c so not compatible with survival. One way to fix this would be to have giant mirrors reflecting light on
