Guest Opinion: Shoreline Bag Ban Not Based in Sound Science

Editor's note: The Washington Policy Center, which describes itself as non-partisan, has been described in the media as a conservative think-tank. The 501 (c)3 Washington Policy Center chooses not to disclose its donors.

The Shoreline City Council will be considering a ban on plastic bags at tonight’s meeting and, like other cities, the arguments for the ban are not based in sound science. In looking at the staff report on the issue from last year, it is clear that some of the claims in the staff report are simply incorrect. In fact, the most recent science demonstrates that banning plastic bags is likely to increase damage to marine wildlife and global warming emissions.

First, the staff report argues that plastic kills millions of sea birds and marine mammals. The staff report claimed “in the United States in 2009, the ecological impacts of this plastic include over a million of sea-birds and 100,000 marine mammals killed by either plastic ingestions or entanglement.” The National Oceanic and Atmospheric Administration has examined this claim and can find no support for it.

On its web page, NOAA notes “We are so far unable to find a scientific reference for this figure.” The only such citation they did find is from 1983 and is sketchy on the numbers, but doesn’t reference plastic bags at all. The study relates to derelict fishing gear. NOAA says “The manuscript does not state that marine mammals are dying from plastic pieces, but rather that mortality is caused by entanglement from lost fishing gear and other unknown causes.” Additionally, the study does not reference the United States. Banning plastic bags would do nothing to address these issues.

While I worked at the Washington State Department of Natural Resources, we were aggressive about removing lost fishing gear in Puget Sound and I can tell you it is a problem for marine life. If the Council is concerned about that issue, they should address it. The staff report, however, is severely misleading and the data are unrelated to plastic bags.

Second, the staff cites a group claiming that “plastic pollution is becoming a hazard for marine wildlife, and ultimately for us.” This is extremely vague but the popular claim that plastic debris is building up in our oceans is, interestingly, false.

Woods Hole Oceanographic Institute found that the amount of plastic in the Atlantic Ocean hadn’t increased over the past two decades. They noted that “One surprising finding is that the concentration of floating plastic debris has not increased during the 22-year period of the study.” It is unclear why this is true, but the amount of plastic seems not to be growing despite the claims of the staff report.

Additionally, oceanographers at Oregon State University also lamented the glut of anti-scientific claims on this issue. Oceanographer Angel White released a statement in 2011, lamenting that claims about the size of the Pacific Garbage Patch were false, noting the actual amount is less than one percent the size of Texas despite popular claims indicating it is twice the size of Texas. She went on to say that “this kind of exaggeration undermines the credibility of scientists.”

These are counterintuitive findings – certainly running counter to the “common” wisdom – but they indicate that the impact of plastic bags on marine wildlife is actually a poor metric to use when determining their environmental impact. Others have, in fact, tried to compare the overall impact of plastic bags to alternatives.

The UK Environment Agency compared the environmental impact of plastic bags to paper bags and reusable bags. They found:

·         Plastic bags have less “global warming potential” than paper bags and a reusable cotton bag must be used 173 times before it breaks even with plastic bags in global warming potential.

·         Paper bags and reusable cotton bags have a greater impact on water quality than plastic bags. Fertilizers used to grow trees for paper and cotton are washed into streams and rivers, depleting oxygen and creating “dead zones.”

Banning plastic bags seems like a straightforward environmental vote. Unfortunately, research by NOAA, Woods Hole, Oregon State University and the UK Environment Agency show such bans are likely to do more harm than good. The simple conclusion is that banning plastic bags would actually increase environmental damage.