Seemingly every year, a common question resurfaces: are reusable grocery bags better for the environment than single-use plastic bags?
2019: “Are Plastic, Paper Or Reusable Bags Better For The Environment?” – Huffpost
2020: “Plastic, Paper, or Cotton: Which Shopping Bag is Best?” – Columbia Climate School
2021: “The Cotton Tote Crisis” – New York Times
2022: “Sustainable Shopping— Which Bag Is Best?” – National Geographic
This is not an easy question to answer– and a lot of the debate around the question (but definitely not all) comes down to local impact (pollution, littering) vs. global impact (most generically in the form of greenhouse gas emissions). And I’m not here to provide a single, definitive answer to this specific question or related questions surrounding other consumer products like electric cars, but want to provide a very, very basic framework (quickly described) for thinking about questions along the lines of: am I making the best decision for the environment locally and globally with this purchase?
The first thing worth mentioning is that the type of framing and questions I will provide are really most relevant for making comparisons between the impacts of different products. The reason I mention that is because there are very few products that are actually provide any net benefit for the environment, and the vast majority of them are related to clean power generation. If you were to map all products produced in the world, most of them would fall in this region of what I’ll call the “GL Chart” (pronounced like “Gill,” let’s say):
Despite the potentially grim message that this chart conveys, it still shows that there are real decisions to be made when it comes to comparing the environmental impact of different products. There is a lot of space on that graph to navigate when it comes to impact-based decision-making, which brings us back to the initial question of how to think about the choice between reusable and single-use grocery bags.
Global Impact
To me, the first step in this super basic framework is to think about the overall global impact of a product from an emissions perspective– effectively, how much energy did it take to create this product or service? I think the five key questions to ask in order to get a general sense for the relative emissions impact of a product without doing any quantification are:
1.Is this product actively exhausting non-renewable fuels during use?This question mostly applies to travel and to any products that use electricity, but is likely the most important question to ask first, since taking a few flights per year can often dwarf the carbon emissions of all your other activities combined. If the answer to this question is “yes,” then it’s likely that the global environmental impact of the product or experience is relatively high.
2. How heavy is this product? There is a lot of material nuance and manufacturing method nuance that can get lost in this question, but in general I think it is appropriate to think about the overall emissions it takes to create and ship a product to be correlated to its weight. The heavier the object, the more energy it takes to produce and move around.
3. How complicated is this product? More complicated products require more energy to manufacture and produce. A few of the many key indicators of complexity in consumer products are: the number of different materials, how many moving parts does it have, the incorporation of electronics, and the use of dying for textiles.
4. How many of this product are there? In general, manufacturing and assembly practices become more efficient as the quantity scales up. As a consumer, this means that products produced in massive quantities are often individually more environmentally friendly than the same product if it were produced in lower quantities.
5. Where did this product come from? With the efficiency of global shipping via boat, this question has less of an impact than one might expect, but if you factor in the prevalence of air freight nowadays, it is worth thinking about how far a product had to travel to reach you (and how far the materials had to travel to the manufacturer). In general, this is an important question to ask, but one that likely has less impact than the others.
These questions above are very difficult to answer in a vacuum without a ton of bespoke industry knowledge, but relatively easy to answer when comparing two products– think about comparing a plastic single-use bag to a car, and it’s easy to make major distinctions in global environmental impact with the questions above. So let’s take a look at two grocery bags that I currently own and run through the comparison questions above:
1. Neither bag is actively using carbon-based fuel sources
2. I would estimate that the Lululemon bag is a couple orders of magnitude heavier than the plastic King Soopers bag
3. It’s a little tricky to put a number to it, but the Lululemon bag is significantly more complex than the King Soopers bag– it has multiple colors, multiple materials, and the manufacturing is not simple
4. I’d guess that there are multiple orders of magnitude more King Soopers plastic bags than Lululemon reusable bags in the world
5. I can’t verify it, but I’d bet both were manufactured in Asia with materials that came from all over the world
All-in-all, these super quick questions would lead me to believe that a high-quality reusable bag like mine from Lululemon probably has a multiple-orders-of-magnitude worse impact on the global environment than a single-use plastic grocery bag. This estimate and its framework does come with a couple of additional clarifications too:First, a lot is made of how long products last (e.g. number of uses for a bag or years operable for a car), and in this framework you can do easy math to extrapolate global impact with the quantity of each product to compare the overall impact of something like using 100 plastic grocery bags or one reusable bag. However, my potentially unfair/unpopular assertion is that the duration of use for most products you are comparing is largely random and unknowable without a ton of research. Second, if a product or service is shared by multiple users, I think it’s generally appropriate to assume that as the number of people using a product increases, the emissions per person decreases. Third, as clean (i.e. non-carbon intensive) power generation becomes more ubiquitous in supply chains, this framework will need to be updated.
Local Impact
This brings us to the next question about how products compare in terms of local environmental impact. Once again, I think there are a few key questions to run through, with each considered from both the user’s and the manufacturer’s point of view— thinking about how the products’ birth and end-of-life affect the local environment, since it is common for a product to cause extreme local environmental harm during creation but low at point-of-use or visa-versa:
1. Does this item produce any byproducts that enter the local environment? In general, creation or use of products that expel chemicals or substances harmful to the local environment like gasses, heavy metals, dyes, micro-plastics, etc. will have a relatively high local environmental impact. Similarly, products that use materials with extreme extraction practices like strip mining or fracking will have high local impact at the point of removal.
2. How is this item normally disposed of when its useful life is over? If a product is intended to be composted, recycled or up-cycled, it will likely have very little local environmental impact when it is disposed properly. The same isgenerally true if the product is contained in a well-regulated landfill as well. Especially in Europe and North America, the way landfills handle and contain material is focused on minimizing impact to the local environment, and landfills can sometimes even produce energy from methane generated within the waste. Similarly, electronics and batteries that are removed from their housings and disposed of properly should not make it to the landfill and can have low impact locally. Products that are not easily contained when they are disposed of properly like radioactive materials, flammable fluids, or toxic materials may have higher local impact. It is worth understanding for your own area how each material or product is normally handled in order to estimate the impacts above.
3. What happens when this item is not disposed correctly, and how often does that happen? This two-part question is a complex one (which often receives a lot of focus due to plastic in the ocean or harming animals), but I will do my best to distill it into a few key considerations. First, the impact of what happens when an item is incorrectly disposed varies based on the where the item ends up. An item that is incorrectly sent to a landfill is likely low-impact, but any uncontrolled disposal into the ocean is a significant problem, and stockpiling of hazardous waste in something like an uncontrolled large urban dump is a massive problem. Second, the severity of the products’ effect on the area it ends up plays a large role in overall impact. A recyclable aluminum can that ends up in the landfill has a much, much lower impact (near zero) than a plastic bag getting wrapped around an endangered animal, and much, much less than a train full of chemicals crashing into a river [LINK]. I would base any estimations of severity, end location, and the resulting overall impact on your every day life and experience (i.e. ignore the example I just provided). Finally, layered on top of everything is understanding how often the mishandling occurs in the (your) local area— what percent of plastic bags end up on the beach, how often are portable phone chargers ending up at the landfill, etc.? My only real advice for estimating how much of a given product is disposed of improperly in your local area is that it is likely much lower than you think— Americans produce an average of ~1800 pounds of trash per year, which translates to a LOT of every product imaginable. The item may seem like it’s littered all over, but it likely still represents a small percentage of overall items.
The last thing I would add before looking back at our grocery bag conundrum is that they’re almost two separate versions of the set of questions above. First, how do these questions apply to my situation specifically? I impact the local manufacturing areas and my own environment by purchasing and using a given product. For those with cleanly-manufactured products and good waste-handling infrastructure, these local environments are not adversely affected, but the same product may have extremely negative environmental effects in other areas it is disposed incorrectly— a good example being a car battery being dumped into a local river. So while it may be the right purchase for you, it might not be the right one for someone in another area, which introduces additional questions around the morality of still purchasing and supporting such a product! (These are not handled in this article, and I will likely never be able to fully comprehend them).
But anyways, to loop back on these questions for our grocery bags:
1. Neither the plastic bag or the reusable one secretes a significant amount of byproduct into the local environment when it is used or disposed. However, it is possible that both (more likely the Lululemon bag) may have negative byproducts from the dying and manufacturing process.
2. The Luluemon bag should likely end up in a landfill when it reaches end of life. It may be up-cycled but does not seem to be high enough quality to achieve it. The plastic grocery bag will likely end up in a landfill, but may be recycled, especially if there is a local chemical recycler like a pyrolyzer.
3. In New England, the waste management system is pretty reliable and waste rarely reaches places it shouldn’t. I would imagine that far less than 1% of each item is not disposed of correctly, but the plastic bag would likely have a slightly higher severity impact on the environment and the wildlife in the forests or even in the ocean.
To summarize the overall local impacts where I live, I would estimate that each of the two bags has a similar effect. Both are generally disposed of correctly and don’t have major differences in impacts if they aren’t.
And wrapping this all together, it allows us to return to our GL chart and place the reusable and single-use plastic bag on the different axes!
In effect, what this basic framework and analysis tells us is that a plastic bag and a reusable one likely have similar levels of local impacts, and a reusable one likely has a much higher overall global impact than the plastic grocery bag, when compared 1-to-1. As mentioned before, the quantity of item you would use may become important in scenarios where you are replacing one product with many of another type, but this process may be difficult given broad uncertainty about replacement quantities and variability in lifespan of consumer products.
Pulling back from the specific grocery bag discussion, though, I hope this framework at least helps you consider some of your own decision making, even if you disagree with any of the specific points or examples made throughout. This type of framework and related questions are really the tip of the iceberg when it comes to eco-conscious thinking, and not meant to supplant diligent research and reading beyond the scope of my knowledge. If nothing else, I would encourage everyone to dig deeper into the topic!
Snow Day 002