Exactly!
Last year I read the Mars Trilogy by Kim Stanley Robinson, and one of the most interesting parts of the series was the ongoing debate around terraforming practices. They were actively pumping all kinds of chemicals into the air to help create an atmosphere, digging DEEP tunnels straight down to release heat from the core, and all sorts of things that sound potentially catastrophic for those of us living on an already-green planet.
I think the only thing blocking us now from terraforming Mars (apart from getting there in the first place) is its lack of magnetic field. We can pump however many gasses we want in an attempt to build an atmosphere but without a spinning liquid core Mars just won't be able to hold onto an atmosphere. Solar winds will strip it away again. In the game Surviving Mars, you can build magnetic field generators but they are costly and require tremendous power. I imagine, if we had the technology, that would be accurate. Is there some other way?