Studies Confirm that a Small Tax Definitely Helps Curb Plastic Pollution
That design helps rule out unrelated trends that affect everyone, such as national shifts in shopping or packaging.
SEATTLE (Scrap Monster): Plastic bags are everywhere, and too many slip into rivers and onto beaches. A new analysis finds that policies that either charge a small fee per bag or prohibit them outright cut the share of bags found during shoreline cleanups by 25 to 47 percent.
The study combed through hundreds of city, county, and state rules passed between 2017 and 2023. It matched those policies to more than 45,000 volunteer cleanups across the United States to see what actually changed on the ground.
The research was coauthored by Kimberly L. Oremus of the University of Delaware’s School of Marine Science and Policy (UDEL).
Oremus and her collaborator set out to measure litter, not just shopping behavior, so the results speak to what ends up in nature.
The team relied on citizen science, meaning trained volunteers recorded what they collected during beach, river, and lake cleanups.
They drew on TIDES, a public database that stores those counts in one place so researchers can analyze patterns across time and place.
To isolate the effect of bag policies, the authors used a Difference-in-Differences approach that compares places with and without new laws over the same period.
That design helps rule out unrelated trends that affect everyone, such as national shifts in shopping or packaging.
The headline result is simple. In communities with full bans or fees, the share of plastic bags in the litter mix fell relative to similar places without policies, and the decline grew in the years after a law took effect.
State level rules tended to be more reliable in the data than city or county policies. Effects looked similar along coasts and rivers, with hints of larger gains along lakes where winds and currents spread litter differently.
Plastic policy: Fees vs. bans
Fees change the default at every checkout and discourage taking a bag when you do not need one, which reduces both thin and thicker bag use.
Other evidence points in the same direction outside the United States. England reports an almost 98 percent drop in single use carrier bags at major retailers since its charge began.
Policies that only restrict thin bags often allow thicker plastic labeled as reusable.
Those partial bans showed the smallest and least precise effects in the analysis, which is consistent with shoppers substituting one kind of plastic for another.
Some states also pass preemption laws that block cities and counties from regulating bags at all. When local governments cannot act, the study’s data suggest statewide policies become especially important.
Courtesy: www.earth.com