The reality of it is that even were we able to start terraforming mars, it would be a few millennia before the changes make enough of an atmosphere to survive. Thats not the worst part. Even after the terraforming is complete the atmosphere on mars would still be to thin to go out wandering without an air tank. Not to mention the fact that the temperatures would still be too cool to be comfortable.
It will be at least 30 years before we could set up some kind of a habitat for semi-continual human presence on mars.
Ahhh...but it is good to dream!