I consider myself a pretty “green” dude. I’m an environmental engineer by trade and my job involves making companies reduce their pollution emissions. I chose this profession and particular position specifically because of my personal ideology. I’m very concerned that climate change is going to make life on our planet difficult for our descendants and is already making life on Earth impossible for some other species. I try to be conscientious about my personal choices and how they affect the ecosystem, and I’m very interested in ways that I can minimize my personal impacts. Naturally, I’ve signed on to a few petitions and I got an e-mail from Change.org suggesting one. But this one in particular I won’t be signing.
Because, honestly, I think that plastic shopping bags are fine and I don’t want them banned.
Carbon Footprint
It seems very counter-intuitive to most people, but plastic shopping bags have a lower global warming potential than reusable plastic or cotton fabric bags. We know that plastic bags are made from oil. And, all things being equal, an item that can be reused multiple times seems likely to be the more efficient use of the resources consumed than one that we use once and dispose of.
However, all things are not equal, and the input resources needed to make a single-use plastic shopping bag are much, much smaller than the input resources needed to make a reusable plastic or cotton shopping bag. The difference is so great that a person who uses single-use plastic bags probably has a lower “carbon footprint” from their grocery container choices than one who uses reusable bags.
In fact, the UK government conducted a life-cycle assessment which determined that you would have to re-use your reusable plastic shopping bag 11 times, or your cotton bag 131 (!!!) times just to break even for global warming potential. In my experience, those bags don’t typically hold up that long.
The truth is that it takes multiple times as many resources to manufacture a plastic bag that can be used multiple times. And a cotton bag requires all sorts of resources (including fossil fuels) to manufacture — planting, irrigation, harvesting, transport, processing, weaving into textiles, so on and so forth — that it’s simply not as efficient as using plastic. Better to use the cotton cloth for clothing.
Waste Disposal
This is the “gotcha”; if you’ve been following me this far, you might say “sure, but carbon footprint isn’t everything. Truckloads of plastic are being dumped into the ocean and are killing aquatic species. And anyway, I don’t like seeing plastic bags being blown around my neighborhood and getting stuck in trees.” And I agree. I have a simple solution, though.
Stop dumping plastic bags into the ocean. It’s pretty fucking easy.
How do the bags end up in the ocean, stuck in trees, etc.? Poor waste management practices. If your local waste collection utility is dumping its trash into the ocean instead of a proper landfill, there’s a Change.org petition you should be signing. There is also an additive to plastic shopping bags that can allow them to biodegrade with a negligible increase to global warming potential. So industry could be doing a lot to keep this waste from being mismanaged, and that’s a cause we could get behind.
But there is a simple choice that you can make to rule out all of those other possibilities, and that is to simply take your plastic shopping bags in to be recycled. Every grocery store I’ve ever been to has a bin at the entryway to return your used bags. Just take them back there to be recycled and viola, they’re not going to kill any sea turtles or get snagged in your bushes.
Of course, you have to remember to take them back. But if you switch to reusable bags, you’ve got to remember to take those as well. So it’s literally the same exact thing.
Yes, it seems intuitive that reusable shopping bags are more “green”; but depending on how you use them (and how you take care of your used single-use bags) the most likely aren’t. If you are more conscientious about taking your reusable shopping bags with you and getting maximum usage out of them, than you are about recycling your waste bags, maybe the best choice for you as an individual is to go with the reusable. But I would argue that most of us simply aren’t in that boat. Therefore, I don’t think reusable shopping bags are a net win for the earth mother.
Hammer & Icicle 