I'll say that I didn't at first either... CO2, so what? It's part of the air we breathe... but when you look into it, especially from a conservative mindset, there are several major problems.
1. The whole "carbon credit" idea is utter horseshit. -- You can keep polluting all you want, just as long as you do something to "offset" your pollution. -- Except for how it doesn't offset shit. It's a made up solution to a problem that doesn't exist.
2. None of this is viable without government subsidies, ie: your tax dollars. A truly "free market" would decide if this is viable or not. Just like wind, solar, etc. If it's so f-ing great, it would produce something of value at a cost the market agrees with, without subsidies.
3. Using "eminent domain" to stomp on landowner rights. -- Moving your CO2 from one place to another does not benefit the general public. It just lines the pockets of corporations and bureaucrats. -- If they can do this, what's stopping them from forcing you to allow a wind turbine, a homeless shelter, (or anything really) in your backyard?
4. There is a safety aspect. A sudden cloud of nearly 100% CO2 would kill you pretty quickly. The "kill zone" would be determined by CO2 volume, wind speed and direction, and dispersion rate, but killing hundreds is not out of the question.