TED-Ed and SciShow on which bags are best and worst for the environment

My environmental science students are working on a project called Hidden Energy in lab this week, which explores how every step in the production, use, and disposal of manufactured items requires energy. In addition, my students have to research the materials used to make the items and their eventual fate after people are through using them. One of my students' favorites over the years has been shopping bags, paper, plastic, and reusable, which I featured in Sustainability of banning plastic bags from DNews and KPBS eight years ago and Paper vs. plastic bags: Student Sustainability Video Festival 73 four years ago.* My answer to the question of paper or plastic then was reusable.

Both TED-Ed and SciShow have created videos about the environmental costs and benefits of shopping bags this past year and their answer is that not all reusable bags are equally sustainable. Watch Which bag should you use? - Luka Seamus Wright and Imogen Ellen Napper from TED-Ed.

Explore the environmental impact of three types of bags— plastic, paper, and cloth— to find out how they’re made, used and disposed of.
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You’ve filled up your cart and made it to the front of the grocery line when you’re confronted with yet another choice: what kind of bag should you use? It might seem obvious that plastic is bad for the environment, and that a paper bag or a cotton tote would be the better option. But is that really true? Luka Seamus Wright and Imogen Ellen Napper explore the environmental impact of each material.

Lesson by Luka Seamus Wright & Imogen Ellen Napper, directed by JodyPrody.

Narrated by Bethany Cutmore-Scott.

I'm not surprised that cotton bags are bad for the environment, while reusable plastic bags are better. Years ago, one of my students presented on how bad cotton was for the environment using an actual cotton plant as a visual aid. It convinced me. Later, another student gave her talk on recycling plastic with reusable plastic shopping bags made from recycled pop bottles as her visual aid. I thought that was a good use for plastic bottles.

SciShow came to a similar conclusion with more scientific detail from what appears to be the same study in The Truth About Green Grocery Bags.

It seems like a simple question with a straightforward answer, but when you look at the total environmental impact of each type of bag, things start to get a little complicated.

Which data one records and analyzes makes a difference on the conclusions. In particular, while climate change is the great existential environmental issue, it is not the only one, so looking at the environment through the lens of climate change alone is insufficient. Remember Commoner's Laws.

Everything Is Connected to Everything Else. There is one ecosphere for all living organisms and what affects one, affects all.
Everything Must Go Somewhere. There is no "waste" in nature and there is no "away" to which things can be thrown.
Nature Knows Best. Humankind has fashioned technology to improve upon nature, but such change in a natural system is, says Commoner, "likely to be detrimental to that system."
There Is No Such Thing as a Free Lunch. Exploitation of nature will inevitably involve the conversion of resources from useful to useless form.

The first, second, and fourth apply, while our intuition about number three, that cotton bags are best, leads us astray. I take that to mean that our intuition about how to apply "Nature knows best" is wrong, not the law itself. After all, reusable plastic bags made from recycled material are still an application of chemical cycling, an application of both Nature knows best and "There is no 'waste' in nature." That's a lesson I plan on passing on to my students, along with these videos.

*The other pair of products are cloth vs. disposable diapers. I might be inspired to look for videos about that, too. If I do, it will be another instance of blogging as professional development.