Actually shouldn't have TOO much effect. I can't comment on the cylinders of CO2 used in pumping or carbonation, but the CO2 that the yeast releases is balanced by the CO2 which the plant absorb in order to produce the sugar that is fermented.
As to how many petrochemicals/fossil fuels are used in the production/creation of those plants and that sugar, that's a different story, but that is less related to alcohol specifically and more to how our agricultural/transportation system function generally.
If it is done in polynomial time, then it would by definition be in P which means it would NOT be NP complete unless P=NP.
I think you are trying to ask how it could be done in less than exponential time (which is how fast the fastest algorithms to solve NP complete problems run).
I personally would expect an algorithm to perform the match would run in O(U*US+K*KS+UI*KI*U) where U=the number of unknown (ie flickr pictures), K=the number of known pictures, US=the average size of an unknown picture, K=the size of the average known picture, UI=the number of interesting things in an unknown picture and KI=the number of interesting things in a known picture. However, it would often run faster because it should be fairly easy to disqualify two pictures as containing any of the same interesting features.