Tuesday, September 4th, 2012
It’s a fact: Plastic shopping bags are greener than paper bags. It’s because they have less impact on the environment. But say that to checkout clerks — or almost anyone else — and they will likely think that you meant to say paper but misspoke, or that you are misinformed, or something worse.
The common assumption that a paper bag is greener than a plastic one is a myth, a false belief, but shared by many who can’t
be bothered with facts. Proving the myth false is done with Life Cycle Analysis (LCA), which totals all of a product’s material and energy inputs and environmental releases from the raw materials used to make it to its end-of-life disposal.
Scientific and comprehensive, LCA can prove difficult to explain briefly and simply, which is why the video below, a TED Talk by Leyla Acaroglu, caught the attention of the American Progressive Bag Alliance.
Acaroglu, the founder and director of Eco Innovators, a consultancy in Melbourne, Australia, is a proponent of systemic Life Cycle Analysis for informed decision-making on strategic sustainability. She is an engaging and easily understood speaker, and as it happens, the title of her six-minute TED Talk is “Paper or Plastic? Debunking an Environmental Myth.”
Her method is a listener-friendly explanation of Life Cycle Analysis applied to the paper vs. plastic bag issue. “Question what you think you know,” she says, about the relative enviro-friendliness of plastic and paper grocery bags. Though she shows that the plastic bag is actually greener, the myth of the paper bag continues because most people won’t take the time to see the full picture of the bags’ environmental impacts.
If you are not familiar with TED Talks, they are presented at three very popular annual TED (technology, entertainment, design) conferences aimed at challenging conventional wisdom by showcasing “ideas that matter” and that spark thought-provoking discussions. Saying the subjects are interesting, widely varied, and surprising is a major understatement.
One note: Although Leyla Acaroglu’s myth-busting explanation of the LCA analysis of paper and plastic bags is excellent, near its conclusion she supports the myth that reusable shopping bags are better for the environment. A study by the UK’s Environmental Agency determined that a cotton bag must be reused at least 131 times to be greener than a plastic grocery bag, and that on average they are reused only 52 times. Plus they need regular hot water washing (think water and energy) to prevent bacterial contamination that can spread serious food-borne illnesses.
That said, Acaroglu’s advice to question what you think you know about grocery bags and her explanation of Life Cycle Analysis are both valid, and form an effective antidote to the mindless repetition of an erroneous myth.
For another quick overview of Life Cycle Analysis, you can download the Life Cycle Analysis Primer put together by the Bioplastics Council, a special interest group of SPI: The Plastics Industry Trade Association. It is not limited to bioplastics and it’s free.