Thursday, January 17, 2013

War on Plastic Bags: Debunking Three Popular Myths

I previously wrote about the unfounded claims on the supposed environmentally baneful effects from plastic bags.

Canada’s Fraser Institute offers their case by dealing with 3 popular myths: (bold and blue highlights mine)
The three central arguments used against plastic grocery bags are that plastic bags pollute the air and water, and pose a significant litter problem, clogging our lakes, rivers, and oceans.

Claim: Plastic bags pollute the air

According to most plastic bag critics, it takes roughly 12 million barrels of oil to produce the 100 billion plastic bags used in the US each year (Sierra Club, undated). 

Environmental activists note the production and decomposition of plastic bags emits greenhouse gases and other pollutants at every stage of a plastic bag’s life (New York Times, 2007). This, however, tells less than half of the story, as most analyses of bag impacts don’t consider the costs and benefits of plastic bags relative to alternatives. 

A study released in 2011 by the Environmental Agency of England helps put environmental impact claims in perspective. In Evidence: Life Cycle Assessment of Supermarket Carrier Bags, researchers offer a “cradle-to-grave” review of seven different types of grocery store bags: conventional lightweight plastic bags; plastic bags treated with a chemical to speed its degradation; a lightweight bag made from a biodegradable starch-polyester blend; a regular paper bag; a heavy-duty “bag for life” made from low-density polyethylene (LDPE); a heavier duty polypropylene bag; and a cotton bag (Edwards and Meyhoff Fry, 2011).
The researchers compared the environmental damage done by the bags using a number of indicators of environmental impact, including global warming potential, acidification, eutrophication, human toxicity, and others. They found that the conventional plastic bag had the lowest environmental impact of the lightweight bags in eight out of nine impact categories and that biodegradable plastic bags had even larger environmental impacts than the regular kind. Paper bags performed poorly on the environmental impact tests, and the study found that they must also be used four or more times to match the global warming potential of the plastic bags. In sum, cotton bags were found to have a greater environmental impact than the conventional bags in seven of nine categories, even when  used 173 times—the number of times needed for its global warming potential to be on par with that of a plastic bag

Claim: Plastic bags pollute the water

Another frequently recited argument in favour of banning plastic is that we face a crisis of plastic-encrusted waterways. Environmental groups paint horrific pictures of plastic pollution like the Great Pacific Garbage Patch, which purportedly spans twice the size of Texas (Oceanic Defense,  undated). Though it’s certainly true that plastic bags can be harmful to all things aquatic, it’s important, again, to put such claims in perspective. As assistant professor of Oceanography Angelicque White reports, the claims about the size of the Great Pacific Garbage Patch are simply wrong (2011). She explains, “The amount of plastic out there isn’t trivial, but using the highest concentrations ever reported by scientists produces a patch that is a small fraction of the state of Texas, not twice the size.” Moreover, “there is no doubt that the amount of plastics in the world’s oceans is troubling, but this kind of exaggeration undermines the credibility of scientists. We have data that allow us to make reasonable estimates; we don’t need the hyperbole.” And the contribution of plastic grocery bags to ocean plastic pollution is relatively small: environmental group Grow NYC estimates that only “7.5% of our waste stream consists of plastic film such as supermarket bags” (2012).

Dangers of alternatives

Alternatives, such as trendy cloth bags, pose a danger. A closer look proves cloth bags are not only less environmentally safe as described above, but they pose their own risks to human health. In June 2010, Charles Gerba and colleagues at the University of Arizona and Loma Linda University released a study on contamination of reusable bags. As they explain in Assessment of the Potential for Cross Contamination of Food Products by Reusable Shopping Bags:

“Large numbers of bacteria were found in almost all bags and coliform bacteria in half. Escherichia coli were identified in 12% of the bags and a wide range of enteric bacteria, including several opportunistic pathogens. When meat juices were added to bags and stored in the trunks of cars for two hours, the number of bacteria increased 10-fold indicating the potential for bacterial growth in the bags.”

While some critics dismissed the study due to its partial funding by the American Chemistry Council, real world examples corroborate Gerbera’s results (Huffington Post, 2012). In October 2010, for example, a teenaged soccer player in Oregon fell mysteriously ill, kicking off a nasty strain of norovirus that quickly spread to her teammates and left scientists puzzled. Epidemiologists ultimately uncovered the bizarre yet treacherous culprit: a contaminated cloth grocery bag from the soccer player’s hotel room. An NBC report explains, “The girl had been very ill in the hotel bathroom, spreading an aerosol of norovirus that landed everywhere, including on the reusable grocery bag hanging in the room. When scientists checked the bag, it tested positive for the bug, even two weeks later” (Aleccia, 2012)

To avoid such dangers, epidemiologist Kimberly K. Repp (whose report on the mystery above appears in the Journal of Infectious Diseases) rightly advises that, “we wash our clothes when they’re dirty; we should wash our bags too.” Unfortunately, however Gerbera et al found that “reusable bags are seldom if ever washed and often used for multiple purposes” (2012).

Economic Impacts

Finally, many proponents of the plastic bag ban spend the majority of their time on environmental benefits, and offer little substantive analysis as to the economic impacts of a plastic bag ban or tax. As it turns out, the economic case for plastic bag bans and /or taxes is less than airtight. A report released in January 2011 by the Suffolk University’s Beacon Hill Institute conjectures that Washington, DC’s bag tax, by making purchases more inconvenient, will lead consumers to reduce how much they buy in the District, which “will eliminate a net of 101 local jobs. The job losses will cause annual wages to fall by $18 per worker and aggregate real disposable income to fall by $5.64 million. The wage and income losses will combine to lower income tax collections.” A recent study from the National Center for Policy Analysis also found that plastic bags cost jobs:

“The NCPA surveyed store managers in Los Angeles County where a ban of thin-film bags took effect in July 2011, to determine the ban’s impact on revenues and employment. Over a one year period before and after the ban, stores that fell under the bag ban experienced a 10 percent reduction in  employment, while employment in stores outside of the ban slightly increased (2012)."


The panic surrounding plastic grocery bags is largely unfounded. Despite continued demonization of plastic bags, the  evidence shows that they’re less likely to be contaminated, typically save more energy than paper or cloth alternatives, and are less hazardous to marine life than is commonly conjectured 
Populist environmental politics has mostly been about misanthropic and atavistic social controls, backed by specious theories, which yearns to bring back society to the medieval age. 

The unseen factor has been the transfer of resources or the promotion vested interest groups, using the environment as cover, such as taxpayer funded green energy industry which has continued to bleed taxpayers dry in the US and in the Philippines, green lobby and the logging interests.

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