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January 26, 2005
Estimating the environmental cost of plastic bag production
According to this article, the San Francisco Environment Department claims that the US uses 12 million barrels of oil to make the 30 billion plastic bags each year. That's disputed, but let's say it's so. That's .0004 barrels of oil per plastic bag. Now, a single barrel of oil (42 gallons) produces 19.7 gallons of gasoline (as well as a bunch of other stuff. Let's say for the sake of argument that gasoline is the only product and so should bear the full externalized cost, so a gallon of gasoline represents .05 barrels of oil, or 125 plastic bags.It's a bit hard to estimate the environmental impact of gasoline consumption because a lot of the cost is carbon emissions, which don't necessarily apply to garbage bags since the carbon is locked up in the bags, but estimates of the total externality hover around $.50. Let's overestimate and say it's $2.00. Since a gallon of gas is equivalent to 125 plastic bags, we can compute the appropriate tax on plastic bags is $2.00/125 or 1.6 cents. Put another way, if we believe that the externalities for plastic bags are associated mostly with production, in order to justify a $.17 tax on bags you'd need a $21 gas tax to match.
Of course, I don't really believe that the major externality from use of plastic bags is associated with production, but then I'm not the one asking for a big tax on plastic bags either.
Posted by ekr at January 26, 2005 8:49 PM | Filed under:
Comments
The article seems pretty clear that their $.17 figure is entirely disposal-related, not production-related.
Posted by: Justin Mason at January 27, 2005 12:29 PM
I think that's correct, but complaints about the environmental cost of production are part of the standard anti-plastic-bag litany. As should be clear from this analysis, they're basically a red herring.
Posted by: EKR at January 27, 2005 12:35 PM