Scientist Says

The Sustainability Paradox: The Pros and Cons of Doing ‘Good’

Mark Falinski, Ph.D.
030421 Blog Swaps

Scientists have predicted that by the year 2050, the oceans will contain more plastic than fish by mass and the largest culprit in this assault on our oceans is single-use plastics. Think plastic shopping bags, take-out containers, and plastic water bottles. You’ve probably seen pictures and videos of plastic bags washing up on shore or straws being pulled from turtles’ noses -- that’s because it is estimated that the 10 million tons of plastic dumped into our oceans every year may result in the death of 1 million marine animals per year. Anyone feeling super cheery yet? 

To counter the harmful impacts of single-use plastics and other environmentally damaging stuff, scientists (ahem, corporate entrepreneurs) have turned to new, more reusable replacements: metal straws instead of plastic ones, cotton totes instead of plastic grocery bags, silicone bags instead of Ziplocs, and e-readers instead of physical books (to cut down on the cutting of trees). While each of these solutions can help cut down on waste resulting from single-use plastics, they each have a pretty significant environmental impact of their own, especially when it comes to climate change. As more people adjust their habits away from single-use and begin to buy more and more reusable alternatives to satisfy the same need, that impact continues to grow. This is what we call ‘The Sustainability Paradox’, which is a frustrating, yet pretty straightforward conundrum: occasionally, in our attempts to buy things that are “better for the planet”, we may end up causing new, unintended damage elsewhere. The good news is that we can overcome or mitigate those consequences with some simple adjustments, but without understanding the impacts of our purchases, it is actually really difficult to do. We are here to help!

STRAWS SUCK

Let’s start by talking about the infamous straw saga. A video goes viral of a straw being pulled from a turtle’s nose and governments, including in the EU and UK, began phasing in plastic straw bans, while companies large and small started cutting straws from their inventory lists. In the wake, a few new options have emerged for those who still wanted to sip their iced latte through a straw, including reusable metal straws, compostable plastic straws, silicone straws, bamboo straws, and paper straws, just to name a few. Naturally, these solutions were a huge hit among all heart-wrenched turtle lovers and individuals that wanted a simple way to do more to support the planet (let’s be honest, there were also a few of us that started getting a real dose of eco-guilt, both self-induced and peer-pressured). A simple Amazon search for “metal straw” now yields more than 1,000 options. This is why metal straws are a great example of the Sustainability Paradox.

When a consumer clicks that “Buy Now” button on Amazon, they do so envisioning the swaths of plastic straws they are diverting from waterways. A metal straw feels like a tangible, visible good deed for the planet. But, we can’t see a metal straw’s socioeconomic, public health, and climate impacts. For example, a study in Brazil from 2020 found that a single metal straw results in the production of more greenhouse gas (GHG) emissions than 1,000 normal plastic straws because a single steel straw also requires more energy during production and uses more materials from the Earth. 

We also ran a quick analysis based off of the data from a Michigan Tech University analysis. We chose this data because it was actually the friendliest study we could find towards metal straws. Even if you only wash the metal straw with cold water and you wash it as quickly as possible, its climate impacts are huge compared to normal plastic straws, paper straws, and compostable plastic straws. One single metal straw would need to be used over 100 times to negate the emissions impacts of making and washing it. Similarly, If you wanted to buy a 20-pack from your favorite retailer, you would need to use that pack of straws nearly 2,500 times to negate the equivalent GHG emissions. (Fun fact: when companies do this type of analysis in more depth, it is often called a Comparative Life Cycle Analysis (LCA) because it is comparing the carbon footprint of the full life cycle of products on a unit by unit basis.)

To put that in perspective, if you used a metal straw from that 20-pack every single day instead of a single-use plastic straw, it would take about seven and a half years to pay off that carbon debt. Here’s a quick graph illustrating how all this math ends up working out on a GHG per use basis:

030421 Blog Swaps Chart 3

What’s the Logic?

Let’s explain this graph a bit more in case you want to try to figure some of this out on your own in the future. The three straight diagonal lines represent the three single-use options (plastic, paper, and compostable plastic), and the curved lines are metal straws in packs of 1, 10, or 20. The carbon footprints (aka global warming potential) of the single-use straws are shown on the Y axis. Every single-use straw you use increases your total carbon footprint due to the emissions from producing each one. Meanwhile, metal straws have a much higher footprint before they are ever even used, due to the much higher impacts from manufacturing. But, there is also a small increase in global warming potential per use that comes from the water and soap used to wash the straw. Just a quick reminder that we assumed the use of cold water, very little soap, and a wash time of ten seconds to make the metal straws look as good as possible. If hot water was used, and the straws were washed for 20 seconds instead, the metal straw would actually never become a more climate-friendly option...yikes.

The goal of this graph is to determine how many times someone would need to reuse metal straws to offset the carbon footprint of single-use straws. To figure this out, locate the point where the lines representing single-use straws crosses the line representing the metal straw pack, and draw a line down to the X axis. For example, the line for a normal plastic straw crosses the line for a pack containing one reusable metal straw at a value of 110. This means that a single metal straw used 110 times has the same carbon footprint as 110 individual plastic straws. This is because the single metal straw has a much higher carbon footprint to begin with, but over time, it becomes the more climate-friendly option. So, if you use your metal straw more than 110 times, you have made the better choice to protect the climate! But, if you are planning on using that straw less than that, a set of single-use plastic straws is actually better for the climate in the long term.

It is definitely worth noting that the lines for single-use paper straws and compostable straws are always above the line for plastic straws, meaning they have a higher carbon footprint per use. That is because studies have shown paper and pulp have incredibly high global warming potentials during manufacturing, making the paper straw’s carbon footprint about 2.8 times higher than that of the plastic one. Meanwhile, compostable plastic straws can only be composted in special industrial facilities and they don’t always naturally break down in the environment. Instead, they are usually sent to landfills, where they can eventually break down into methane (a greenhouse gas that is 28 times more potent than carbon dioxide), while normal plastic straws do not. As a result, the global warming potential of compostable plastic straws, over the course of their entire “lifetime”, is roughly 3.1 times greater than for normal plastic straws. 

Of course, we also need to talk about the waste factor. Sure, every time you use a metal straw you are theoretically diverting plastic from the ocean, but only 1 in every 5,000 pounds of ocean plastic is related to plastic straws and only 1 in every 4,000 plastic straws actually makes it to the ocean. That means if you use a plastic straw every single day for 11 years straight, only one of those straws will find its way into the ocean, on average. 

What Should I Do?

All this to say: don’t put too much pressure on yourself if you want to use a straw and ease up on the peer pressure associated with straw-mageddon. Also, some folks need to use straws for health or ability reasons, so we don’t want to be absolutist about how to take action. If you read this and have no idea what to make of it, here are four key paths forward, depending on what works best for you and your lifestyle:

  1. If you’re able to, then try ditching straws altogether. Cups have been suitable drinking vessels for centuries. 
  2. If you’re the type of person that can carry reusables around with you, then we would recommend buying one straw made out of a reusable material and sticking with it.

If you’ve bought a reusable straw, get to your fav coffee shop and realize you forgot it at home, take a plastic one instead of buying another metal one. If someone gives you that evil condescending look condemning your single-use betrayal, then you can smile back at them knowingly because you have data and science in your back pocket.

IT’S IN THE BAG

Grocery bags are another fine example of the Sustainability Paradox. A game-changing study out of the UK back in 2011 looked into the environmental impacts of all kinds of shopping bags. We decided to play with the data ourselves to check out a few things. What we found was that, just like straws, it turns out that you will need to use your reusable bags and paper bags quite a bit to offset their carbon footprint. For example, a single paper bag actually has three times the carbon footprint of a plastic bag. This is because cutting down trees removes one of the Earth’s amazing natural carbon dioxide sinks, producing paper actually requires a ton of energy, and when paper breaks down in the environment it can release methane, which is much worse for the climate than carbon dioxide. This variation in potency is called the ‘global warming potential’ of various gases and it’s why we consider more than just carbon dioxide when we evaluate GHG emissions. So, if you go with the paper bag route at the grocery store, try to reuse those paper bags as much as possible. We’ve also heard of some people that use their paper bags to collect their food scraps for compost, but that’s a whole other can of worms...

030421 Blog Swaps Chart 2

Just like in the straw graph above, the point at which the lines for two bags cross represents the number of uses where their carbon footprints become equal. The only difference here is that the reusable options are horizontal lines because shopping bags aren’t regularly washed, like straws are. So, you would need to use an LDPE (low-density polyethylene) plastic bag more than three times to offset its carbon footprint, and you’d need to use a thicker polypropylene bag more than ten times to do the same. Believe it or not, the real kicker here is those cotton tote bags. Those bags would need to be reused more than 100 times to offset their carbon cost. To put that in perspective, if you went grocery shopping once a week, it would take two years to offset the carbon footprint of a single cotton tote bag compared to a pile of single-use plastic bags. So, the story here remains the same: because of the Sustainability Paradox, the answer is to be smarter about using the existing reusable bags you have and know when it makes more sense to use something else. Finch doesn’t believe in guilt tripping, but that doesn’t mean we’re all off the hook and should go around grabbing plastic bags all willy nilly. If you forgot your reusable bag at home, opt for a paper or disposable plastic grocery bag instead of buying a brand new reusable cloth bag.

OTHER JUNK

We thought it would be interesting to check out a few more examples where we might innately think the reusable option is better. For simplicity, we just looked at the carbon footprint of these different products since that is tracked really well by scientists, but any full analysis should take into account way more than just global warming potential. Stay tuned for future posts about other ways to measure the impacts of your products, including how we all can limit things like water use, carcinogen concerns, and damage to our lakes and oceans. Some of what you’ll see here also reflects the independent studies we continue to run here at Finch behind-the-scenes. Within the below chart, we have some single-use stuff in orange and some reusable stuff in blue. The number next to the reusable stuff is how many times you would need to use it to offset its carbon impacts.

030421 Blog Swaps Chart

(We’ve also linked to some of the resources we used for each value in case you want to get into the weeds with us: UW-Madison Office of Sustainability ; MIT Office of Sustainability ; New York Times; Huhtamaki; Jeswani, H.K., Azapagic, A. Clean Technology Environal Policy ; Alejandro Gallego-Schmid, Joan Manuel F. Mendoza, Adisa Azapagic, Journal of Cleaner Production. )

As you can see, a lot of the stuff we buy comes with a hefty environmental price, but with enough use, it is actually pretty easy to offset those impacts. For example, once you buy an e-reader, you only need to read 45 books to offset its related emissions (by the way, we suggest downloading “Silent Spring” by Rachel Carson -- the original book about environmentalism, the eye-opening Dorceta Taylor book about environmental racism, “Toxic Communities”, or the Dieter Helm book “Net Zero: How We Stop Causing Climate Change” to start off your e-reader collection). All of these re-use scenarios are achievable and, as long as you focus on reusing rather than replacing, you too can offset the carbon footprint of the stuff you buy and successfully avoid the Sustainability Paradox

RECAP

We just threw a lot of confusing and seemingly contradictory information at you and honestly, we are just scratching the surface of the world of sustainability. The most important thing to remember is that there is no single answer to being “sustainable.” Making the planet a more habitable place is an imperfectly weird mix of qualitative and quantitative data that’re both subjective and objective. No matter what, all seemingly “sustainable” choices come with tradeoffs and that’s why we believe in choosing wisely vs. just believing when brands say they’re “green” or “clean.” 

The bottom line here is simple: we think reusable stuff is way better than single-use stuff, but it’s only better for the planet if you actually reuse it!

Here’s a quick summary of what to do if you’re feeling stumped:

  1. When you buy something reusable, reuse it. This may seem obvious, but the more times you reuse something, the lower the environmental impact it has per use.
  2. Figure out your own sustainability goals and acknowledge others’ goals may be different. We all want to do it all right; stop climate change, save the turtles, use less water. But, trade-offs inherently exist. Figure out what is most important to you and try to reach those goals. At the same time, make sure to help others reach their own goals even if they’re not the same. Think about sustainability as a team sport.
  3. Avoid stocking up on too much reusable stuff. We all make mistakes. Avoid the temptation to buy another metal straw or reusable bag, unless you plan on using it hundreds of times. Sometimes the more sustainable option is to choose the disposable thing one time. Just don’t make it a habit.
  4. Consult the experts. There are so many factors to weigh and it can all get a bit overwhelming. When in doubt, try to avoid baseless marketing claims and lean on the word of scientists and experts in the field to try to make the best decisions based on real data.

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