Hi Hairball, No, they don't want to tax the air, otherwise I would never had said I like this. In the whole text of that part, they imply that Kyoto is so last-decade and out-of-date. They suggesst that the global community come up with a new plan. That plan includes regulations of C emmisions based on the free market.
Since all C emmiting industries will want to buy some of that total cap, the price/kg/year of the cap will increase (demand). So, either the industries spend money to change their processes to reduce emissions, or they fork out the dough. They will do what is best for their bottom line and the market will determine a price for those "shares" of the emission total based on its overall supply.
I like the plan since it ensures regulations on C emissions that are equitable for all countries.