[rhelz]

That was exactly my point. What makes the co2 referred valuable is not that it is co2. We literally (not metaphorically, or hyperbolically, but literally) are surrounded by the stuff every day of our lives.

What makes it valuable is that the co2 is concentrated and under pressure. But pretty much any gas would fit the bill.

And let's not forget, the original article was about MIT scientists making extracting co2 from the atmosphere "more efficient". Which, as you point out, is a rather hopeless quest---in order to get the co2 back out of the atmosphere, you'd need more energy than you got from burning whatever put it there in the first place.

So making any meaningful dent in the atmospheric co2 by extraction/converting a mug's game. You'd need on the order of the entire amount of energy used by the human race during the entire industrial age.