The major greenhouse gas is water vapor. How can we possibly control this, industry or not?
We can easily manipulate the level of water vapor in the atmosphere; it's just not economical to do so. Just because something isn't worth being done doesn't mean it can't be done.
If it's unclear, I responded to the above because my impression was that you're casting doubt on our ability to terraform Mars, based on our not having resolved the global warming issue for Earth. If that's the case, then even leaving aside the obvious logical fallacy your statement is wrong on its face. We know how to terraform Mars right now if we want to, it just requires the investment of resources to get it done.
Adding water vapor is a relatively straightforward exercise that could be done on Mars or on Earth if the reason and the will existed. Removing water vapor would be more dicey, but there's certainly no need to do that in order to terraform Mars...