>> In a closed system, you can't reverse something by using less energy than that which went into creating it.

>> Basic physics. From that principle there's only one possibly conclusion when it comes to climate change: We can't do a damn thing about it.

I agree that the climate crisis is grim and that geoengineering is not a cure all. I do not think your reasoning makes much sense. Say it takes 100x as much energy to capture C02 as to create it. If the energy it takes does not warm the atmosphere it is not a problem. For example, if solar energy was removed to C02 it would not contribute to the warming of the planet either by directly releasing heat or a greenhouse gas.