To Ban Or Not To Ban Plastic Bags? That's Not The Best Question

03/28/2017 10:41 am ET Updated Mar 29, 2017

The Boston City Council this week is considering a controversial proposal that has been trending in many municipalities. It’s a proposal that has widespread daily impacts on citizens and businesses and stimulates unusually fiery passions: banning plastic bags.

Along with reducing visual pollution and solid waste, a primary goal of Boston’s proposal is to reduce marine pollution, something I’ve investigated for decades. But when proponents and opponents of bag banning ask me whether a ban would meaningfully achieve the goal, I give them an answer that neither they, nor I, nor society is satisfied with: We don’t really know.

We know plastic products have negative impacts. The images of turtles ingesting plastic bags that look like their favorite food, jellyfish; of birds and seals choked by six-pack holders; of bags polluting beaches, and the Great Pacific Garbage Patch all provoke legitimate sadness and concern. A plastic bag ban is a relatively quick and painless, and clearly beneficial, action to address marine pollution, but it highlights society’s mixed relationship with science and its role in public policy.

To develop effective public policy, policymakers must evaluate and balance several factors and perspectives, including economics, the environment, quality of life, and science. But in reality, stakeholders aren’t so egalitarian in weighing all the factors.

I learned just how charged the debate on banning plastic bags can be in 2013 when I testified on proposed legislation by the State of Rhode Island to ban plastic bags. As a scientist, I don’t come down on either side. My job is to investigate and compile objective evidence that should inform wise decisions and effective policies. In my testimony, I cautioned against drawing any conclusions about whether banning plastic bans would or would not effectively help mitigate marine pollution—without having rigorous research to prove those conclusions. But my statement was either misconstrued or misused by advocates on both sides who labeled me as against the ban—and misinterpretations of what I said still linger as “alternative facts” on the internet.

Plastics are going to continue to flow into the ocean for decades from a variety of sources beyond bags: microbeads, bottles, containers, balloons, pellets, etc. Minimizing any individual source is helpful, but it is important to understand and weigh the relative costs and benefits of policy decisions—to help focus limited public and private resources on those which will have the greatest impact.

But we lack a comprehensive and rigorous scientific understanding on the relative sources of plastics that reach the coastal and open ocean; how they behave, react, and degrade; how far they travel from land and, if and when, they sink; and the injuries they impact at each and every level of the entire ecosystem. To gain that understanding requires an investment in additional research. If society really wants to implement effective public policies that make progress toward reducing this major problem at all levels—locally, nationally, and globally—it will have to devote more time and resources to find them.

As plastic bag banning proposals continue to pop up in coastal communities across the country, I wonder if we will finally decide to devote the resources needed to meaningfully answer the question about plastic bags? impact on the environment? And while plastic pollution is also a visible problem, will we devote as much passion and energy to less visible marine pollution issues where the science, in fact, is clear?

Ironically, when I testified in Rhode Island, I noted that its coastal waters faced problems that were well recognized by scientific research and demanded attention. One problem, which Massachusetts also faces, is runoff or leakage from yard, farm, and golf-course fertilizers, faulty septic systems, and sewage overflows that are overdosing the ocean with nitrogen. This has caused fish kills and have been linked to harmful algal blooms that threaten food supplies, economic hardship, and public health.

Rhode Island didn’t ban plastic bags, and we cannot say what impact that has had. But nitrogen pollution has likely led to the closure of shellfish beds and had large economic impacts on Rhode Islanders.

In today’s polarized society, science can be the honest broker and should be weighed in among the emotional and economic arguments. Unfortunately, science doesn’t provide instant, black-or-white answers, or in some cases, the answers people want to hear. But it’s not good for society when science is misconstrued or ignored.

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