As nice as it is that San Franicisco (SF) is leading the way on sustainabilty in the most recent round of city rankings (see also the Seimen's Green City Index) how close is SF or any of the other cities to sustainability? How would we know? This is the million dollar question of sustainabilty. Without being able to answer it, one has no legitimate claim to sustainability assessment. (see other S2030 Clips post here).