Monday, 13 July 2015

Banning the bottle leads to more bottles sold

Every now and again there is a call to ban bottled water from my university campus. The call comes from the environmental lobby, and points to the amount of plastic bottles entering the waste stream (even though recycling is available and fairly prominent on campus). The expectation is that, if bottled water were not available, students and staff would make use of refillable bottles and/or bring their own water from home.

Last month Timothy Taylor pointed out an interesting and pertinent article from this month's American Journal of Public Health, by Elizabeth Berman and Rachel Johnson (University of Vermont, Burlington), entitled "The Unintended Consequences of Changes in Beverage Options and the Removal of Bottled Water on a University Campus" (gated; I don't see an ungated version anywhere). The authors evaluate the impact of two policy changes at the University of Vermont at Burlington, that were designed to improve the health of the university community, and to reduce plastic waste:
First, in August 2012, all campus locations selling bottled beverages were required to provide a 30% healthy beverage ratio in accordance with the Alliance for a Healthier Generation’s beverage guidelines. Then, in January 2013, campus sales locations were required to remove bottled water while still maintaining the required 30% healthy beverage ratio.
Fortunately the authors didn't attempt to disaggregate the effects of the healthy beverage ratio separately from the ban on bottled water - this would have been difficult to do, given that there could be other differences in beverage consumption between fall and spring (the baseline data were collected in the fall 2012 semester, and the final data in the fall 2013 semester, with data from the spring 2013 semester occurring in-between the introduction of the healthy beverage ratio and the ban on bottled water).

The results they obtain are especially interesting, and illustrate the unintended consequences of the combined policies:
Per capita shipments of bottled beverages did not change significantly between spring 2012 and spring 2013 (P=.71) but did increase significantly from 21.8 bottles per person in fall 2012 to 26.3 bottles per person in spring 2013... Calories, total sugars, and added sugars shipped per capita also increased significantly between fall 2012 and spring 2013...
So to summarise, the number of plastic bottles going to landfill increased following the ban on bottled water. And to make matters worse, consumers were purchasing more unhealthy beverage options. This was in spite of the best efforts of the authorities:
The university made several efforts to encourage consumers to carry reusable beverage containers. Sixtyeight water fountains on campus were retrofitted with spouts to fill reusable bottles, educational campaigns were used to inform consumers about the changes in polity, and free reusable bottles and stickers promoting the use of reusable bottles were given out at campus events.
The university authorities assumed that by banning bottled water, consumers would switch to tap water from water fountains. However, tap water need not be the beverage option that provides the next highest utility (satisfaction) for the consumer - for many consumers, it appears to be flavoured water (which was not affected by the ban), sugar-free drinks, or sugar-sweetened drinks. As Timothy Taylor explains in his blog post:
This finding is not an enormous surprise, because a reasonable amount of survey data suggests that many people switch from sugar-sweetened drinks to bottled water, and that if bottled water isn't available, many of them will switch back.
Perhaps the university should wind back the ban on bottled water and stick with the healthy beverage ratio alone - at least through a spring semester so that it can be compared like-with-like to examine its effects. And perhaps my university should take note the next time this sort of policy is considered.

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