Many cities have implemented bans on free, single-use plastic bags to reduce environmental pollution.
However, a recent study has shown that these bans can have unexpected consequences, even after they are lifted, writes El Economista.
The study, published in the Journal of Marketing Research, was co-authored by Hai Che, a marketing professor at UC Riverside.
It looked at the effects of the plastic bag bans in Austin and Dallas, US cities where the restrictions were eventually reversed.
The research revealed that after the ban was lifted, sales of plastic bags went up significantly.
While the goal of the ban was to reduce plastic bag usage, the data showed that people ended up buying more bags, often using them as trash liners for their homes.
This increase in consumption was surprising to the researchers, who expected people to buy fewer plastic bags.
Despite this, the study also found some positive results. The ban encouraged some people to use reusable bags, even though the researchers didn't have specific data on this behavior.
Professor Che pointed out that the use of reusable bags was a significant change that may have been influenced by the ban.
The study also analyzed how long the effects of the ban lasted. In Dallas, after the 5-cent charge was removed, plastic bag sales returned to pre-ban levels after about 13 months.
In Austin, sales remained 38.6% higher than before the ban, even after the policy was repealed.
To understand the environmental impact, the researchers did a "break-even analysis."
This showed that to maintain sustainable levels of plastic bag use, people would need to reduce their use by one bag for every seven trips in Dallas and one for every five trips in Austin.
While the policies did cause some negative effects, they could still have a positive environmental impact.
The study suggests that even after policies are repealed, they may still lead to beneficial environmental changes.
However, policymakers should be aware of unintended side effects. Similar effects have been observed with other policies, like those targeting sugary drinks or energy efficiency.
