When Mayor Bloomberg announced his “doomsday” budget on Friday (seriously, can we think of something less gloomy, please?) one item that caught our attention was the five-cent plastic-bag tax, which is expected to generate $100 million for the city. Bloomberg made a similar proposal last November, igniting a debate between those concerned about the fate of the environment and people more focused on the fate of their nickels. But back then, it was only expected to generate $16 million. Had something changed, besides the city’s increasing desperation for funds?

Mayoral spokesman Jason Post tells us that not only did a new Waste Characterization Study helpfully result in a less conservative estimate for the bag-tax revenue, but that the scope of the fee has expanded beyond its original targets. Whereas the old program limited the five-cent charge to purchases at groceries and bodegas, the new plan will affect any business that uses plastic bags, such as department stores. So how confident are they in the new $100 million figure? “Fees and taxes are notoriously hard to estimate,” Post says. “We think it’s a good one. Is it accurate? Until we try it, we’ll have to see.” It may be some time before we find out — it was still unclear to Post whether the tax needed to be approved by the City Council or by Albany.