Most people would agree that we need to look after our planet so that we and future generations can enjoy it. I certainly feel that way and it is good to see so many articles bringing attention to the topic. They make people want to act. Our leaders, major corporations and even children are demanding action. But what actions are the wisest? How can we be sure that we are helping and not harming our environment? As a scientist, I wanted to see the facts, but I didn’t find any in the articles online. Hardly any of the articles referenced scientific studies. I began to realize that just about all we believe about the environment is based on LinkedIn headlines, YouTube videos and articles that are just opinion pieces, without any solid foundation. That made me uneasy. As you will see, virtually everything we have been told about plastics and the environment is a lie. When you check the science, it reveals a very different picture.
This page is the culmination of my personal search for all the solid data I could find. I hope this is a valuable resource for the public, for teachers and for journalists who care enough about the environment to spend a few minutes learning the truth. Only then can we make good decisions. At the moment, policy decisions are being made based on a web of lies. If you are in a hurry, you can scroll down to the Conclusions section.
Why did I start down this path? I had been reading a lot of articles online about plastic bags and proposals to ban them. But I did not see a single piece of data to support that decision. It may surprise you to hear that I find plastic bags to be one of the ugliest things imaginable. However, I realise ugliness alone is not sufficient reason for a ban. So, with all the options including paper, cotton, conventional PE bags, reusable PP bags, biodegradable plastic bags and so on, how can we know which one is best? There are many different companies telling us their bags is green, but how do we know who is right?
I used Google and looked for the terms “plastic bag lifecycle analysis” and “plastic bag LCA” because lifecycle analysis is the only internationally accepted standard to determine what is good and bad for the environment. GreenPeace uses it and so do governments and major companies. It’s expensive and includes everything from cradle to grave including all the “inputs” (raw materials and energy), and “outputs” (emissions to the air and water, by-products and wastes disposal) for making a product. Because it’s so expensive, I wasn’t sure I would find any, but I was happily surprised to find some right away. You can type “LCA plastic bag” into Google and find many of the same hits I did. These are all the studies I have found at that time.
To avoid “spin”, these are exact quotes copy-pasted from the executive summary or conclusions of each study:
“A compilation of all of the statistically-based, scientific studies of litter in the U.S. and Canada over an 18 year period shows consistently that “plastic bags” (which includes trash bags, grocery bags, retail bags and dry cleaning bags) make up a very small portion of litter, usually less than 1%.”
“Our results also show that Paper bags, even with 100% recycle content, have significantly higher average impacts on the environment than either of the reusable bags or single-use plastic retail bags”
“Our results in this study show that these regulations and policies may result in negative impact on the environment rather than positive. Even though Paper bags come from a renewable resource and are easily recycled, it is likely that they are not the best environmental choice.”
In summary, they found that paper bags are much worse for the environment and that the best two choices were reusable polypropylene bags or single-use polyethylene bags.
“The conventional HDPE bag had the lowest environmental impacts of the lightweight bags in eight of the nine impact categories.”
“The paper bag has to be used four or more times to reduce its global warming potential to below that of the conventional HDPE bag, but was significantly worse than the conventional HDPE bag for human toxicity and terrestrial ecotoxicity due to the effect of paper production. However, it is unlikely the paper bag can be regularly reused the required number of times due to its low durability.”
“The cotton bag has a greater impact than the conventional HDPE bag in seven of the nine impact categories even when used 173 times (i.e. the number of uses required to reduce the GWP of the cotton bag to that of the conventional HDPE bag with average secondary reuse). The impact was considerably larger in categories such as acidification and aquatic & terrestrial ecotoxicity due to the energy used to produce cotton yarn and the fertilisers used during the growth of the cotton.”
They also found that plastics designed to degrade were worse for the environment. Non-woven, reusable polypropylene bags have least environmental impact if people actually reuse them several times but in reality, people forget to do so.
“The study results support the conclusion that any decision to ban traditional polyethylene plastic grocery bags in favor of bags made from alternative materials (compostable plastic or recycled paper) will be counterproductive and result in a significant increase in environmental impacts across a number of categories from global warming effects to the use of precious potable water resources.”
“This study supports the conclusion that the standard polyethylene grocery hag has significantly lower environmental impacts than a 30% recycled content paper bag and a compostable plastic bag.”
“Proponents claim that banning plastic shopping bags will benefit the environment. Yet, as this study has shown, there is very little empirical support for such claims. Indeed, the evidence seems to point in the other direction for most environmental effects. Some of the alleged benefits are simply false, such as the claim that eliminating plastic bags will reduce oil consumption.”
“Unfortunately, policymakers have been cajoled into passing ordinances that ban plastic bags. That is bad news for consumers. It is also bad news for the environment, since the public has been misled into believing that by restricting the use of plastic bags, the problems for which those bags are allegedly responsible will be dramatically reduced.”
“In general, LDPE carrier bags, which are the bags that are always available for purchase in Danish supermarkets, are the carriers providing the overall lowest environmental impacts when not considering reuse. In particular, between the types of available carrier bags, LDPE carrier bags with rigid handle are the most preferable. Effects of littering for this type of bag were considered negligible for Denmark.”
They found that single-use PE bags or reusable PP bags were better for the environment than paper, unbleached paper, conventional cotton bags, organic cotton bags, biopolymer bags or any other types of bag.
Once again, we see that PE and PP win over so-called “green plastics” or renewable options. This is a wake-up call that renewable or “green” alternatives can be much worse for the environment than the materials what we already use now.
“Reusable plastic bags can reduce the amount of green house gas emissions, solid waste generation, and acid rain pollution than single-use polyethylene plastic bags. The plastic bag with the least amount of environmental impacts would have the following features:
♦ Made from recycled plastics
♦ Lightest weight possible
Currently, PP non-woven bags could not be produced from PCR due to the lack of recycling infrastructure in the United States. However, PE reusable bags could be made with PCR in concentrations of 40% to 100% PCR. Likewise, single-use plastic bags can be produced with 40% to 100% PCR. The use of PCR can offer significant environmental benefits for reduced carbon dioxide emissions, reduced solid waste, and reduced pollution.
The polyethylene based reusable bag with 40% PCR is the plastic bag with the least amount of environmental impacts. The reusable bags though will require more fresh water than a single-use polyethylene bag due to the washing requirements of the bags that carry meats and dairy products.”
“The studies show that bioplastic bags have some advantages in the production life cycle phase (from cradle to door), but can be questionable in the end of life cycle phase, if not properly disposed and/or composted industrially instead in domestic compost bins. It was shown that long life (PP) carrier bag is by far the best choice if used for five years as proposed by manufacturer.”
Another study showing that so-called bioplastic bags are not friendly and that reusable PP bags are the best choice.
“As a first order assessment, it can be reliably concluded that plastic bags have a smaller environmental footprint for use ratios of up to 2.5 plastic bags to one paper bag. Above this ratio, the uncertainty of data accuracy is too high to form reliable conclusions. Only for very high ratios of 7:1 and above does the paper bag begin to compete with the plastic bag.”
“All in all and based on the detailed results shown in this report here, we can conclude that the shopping bag ECOLOOP – under the here used boundary conditions – is the ecological winner, followed by the ‘I’m green’ shopping bag.”
The ECOLOOP bag is made from recycled LDPE type polyethylene. The I’m Green bag is made from a renewable type of polyethylene which is commercially available (for example from Braskem). As with all the other studies, these plastic bags were far greener than paper, cotton or biodegradable plastic.
“The smaller reusable HDPE bag uses more material to achieve the functional unit, and as a result the reusable HDPE bag becomes equal to that of the PP Box. The next best alternative is the reusable PP bag.”
“In terms of primary energy used, the preferred option is still the reusable woven HDPE bag, followed by the PP box and the reusable PP bag.”
“In terms of global warming potential, the preferred option changes from the reusable HDPE bag to the PP Smart Box, followed by the reusable HDPE bag and the reusable PP bag”
After comparing cotton, paper, bioplastic, single-use and multi-use bags, they concluded the above. Namely, that the HDPE and PP materials gave the lowest environmental impact.
This study looked only at carbon dioxide emissions and concluded that all the plastics were far better than natural materials like jute or paper. Interestingly, they concluded that PLA was slightly better than PE, PP and PET. Other studies looking at all the other factors all agreed that PE and PP were a better choice than PLA or other biopolymers. I did not include a quote from the conclusions section in this case because there was no such section from which to quote.
This study reviewed studies to date on compostable packaging and also food service ware (FSW), which is unusual.
Summary of Compostable Packaging Studies:
“While compostable packaging represents a small share of the packaging market, consumer interest in sustainability has increased demand for it (Meeks et al. 2015). Unfortunately, the studies included in this review suggest that the use of compostable packaging has signficant environmental tradeoffs when compared with non-compostable materials and other end-of-life packaging management practices. Results suggest that other waste recovery strategies, such as recycling, may be preferable when considering the disposal of a specific compostable packaging material.”
Summary of FSW LCA studies:
“The available studies indicate that some, but not all, of the conclusions drawn from the review of the various attributes for packaging also apply to FSW. No LCA studies providing midpoint impact results for FSW with recycled content were identified. We found that recycling of FSW products generally results in lower impact potentials when compared with landfilling or incineration. Biobased FSW is generally not preferable to fossil-based FSW. This is because production impacts for biobased materials tend to be higher than for conventional materials. Compostable FSW is generally not preferable to non-compostable FSW, as they are generally biobased, resulting in higher production impacts than fossil-based materials, and receiving less credits at end-of-life than other waste management options.”
“The literature on LCA of plastic waste management systems is vast and the results reported are generally consistent, showing that recycling has the lowest environmental impact on Global Warming Potential (GWP) and Total Energy Use (TEU) impacts. On the other hand, the literature addressing the economic assessment of plastic waste, namely the various End-of-Life (EoL) treatments, is rather limited. Other methodologies, such as integration of LCA and Life Cycle Costing (LCC) of plastic products, are almost never addressed. In any case, the overarching conclusion is that plastic materials usually have environmental and economic advantages over conventional materials throughout their Life Cycle, with or without consideration of the EoL stage.”
They conclude based on a review of many LCAs that we should pay more attention to the end of life aspects but even accounting for that, plastics are usually better for the environment than conventional materials.
“For all indicators under study (Primary Energy Demand, Global Warming Potential, Eutrophication
Potential, Acidification Potential, Smog Potential, human and ecosystem toxicity ), most of the impacts
are associated with the distribution and use phase. The polymer substrate shows benefits over cotton
for all main phases of the life cycle:
The polymer (polypropylene) bank notes are clearly superior to cotton. This LCA is not on grocery bags but I thought it important to see whether the LCA analysis changed when applied to other end products. It seems that the plastic is more friendly in bank notes too.
“When comparing substrates, it is seen that for a given mass of bank notes the paper substrate generally has slightly lower environmental impacts than the polymer substrate. However, because polymer bank notes are assumed to last 2.5 times longer than paper bank notes (the default assumption in this study) a significantly lower mass of polymer bank notes are required to satisfy the functional unit. Hence, overall polymer bank notes have lower environmental impacts than paper bank notes for all impact categories assessed except for photochemical ozone creation potential.”
“The sensitivity of the results to the default lifetime has been assessed. It was found that polymer bank notes need only have a lifetime 1.33 times greater than that of paper bank notes to achieve a lower global warming potential. Based on experience of from other countries that use polymer bank notes it seems very likely that this lifetime will be exceeded, indicating that the overall conclusions from the study are robust.”
This is another study showing that polymer (polypropylene) is far superior to paper in terms of almost every indicator of environmental impact.
“In other words, and compared to total global emissions of 46 GtCO2e in 2005, there would have been 3.6 to 5.2 GtCO2e, or 8 to 11 percent, more emissions in 2005 in a world without the chemical industry.”
and goes on to say…
“The biggest levers evaluated for emissions savings enabled by the chemical industry were:
This report was performed by McKinsey but was funded by the chemicals industry. They found that overall, the chemicals industry saves carbon dioxide in large part due to plastics used as heat insulation, packaging, automotive plastics and piping.
the respective packaging mass would on average increase by a factor 3.6
life-cycle energy demand would increase by a factor 2.2 or by 1,240 million GJ per year, which is equivalent 27 Mt of crude oil in106 VLCC tankers or comparable to 20 million heated homes
GHG emissions would increase by a factor 2.7 or by 61 million tonnes of CO2-equivalents per year, comparable to 21 million cars on the road or equivalent to the CO2-emissions of Denmark.”
They conclude that replacing plastic packaging would require vastly more alternative materials, far more energy and lead to far more carbon dioxide emissions.
Lifecycle assessments (LCA) are the only internationally accepted method for comparing the environmental impact of materials and products. They are used by governments, companies and environmental groups, including GreenPeace and are independently audited. The LCA method takes into account all the energy, materials, water, emissions and so on associated with the manufacture and disposal of a product. No tool is perfect, but LCA is by far the best, most widely-accepted way to see what is really green.
LCA analyses are done by government agencies in the US, Canada, UK, Australia and Denmark. They all agree that the single-use polyethylene bags we use today have much lower environmental impact than potential replacements such as bioplastics, paper, unbleached paper, cotton or organic cotton. The other leading green solution is reusable PP bags (think of the iconic blue Ikea bags). Those are actually the best option, as long as they are reused several times.
To replace plastic bags with paper bags requires 2.7x more energy, 1.6x more carbon dioxide emissions and 17x more water usage. It has also been estimated that replacing the plastic bags in the EU would require cutting down an astonishing 2.2 million more trees per year and require 60 000 Olympic swimming pools more water.
I believe this to be the largest collection of LCA studies on this topic. Why did I spend so much time to collect every study I could find? The reason is that this is an important topic and people are convinced that plastic is harming our environment. Because the findings go against popular opinion, there is an added burden of proof when trying to dispel the myth that has evolved around the topic. If I had found one LCA that said plastic was better, or if I had found only a couple of studies funded by the plastics industry, I would have been skeptical. Instead what I found instead was multiple studies from several countries and all of them funded by impartial parties. The conclusions are unanimous and solid. I asked an LCA professional to review all 24 lifecycle reports I have found on grocery bags and here is what he wrote:
“From all 24 reports and reviews assessed, the actual LCA analyses on grocery bags overwhelmingly point to plastic (HDPE) as the material with least environmental impact, both at single use level and multi-purpose.”
Neil Shackelton – Founder Medoola
If every study ever done anywhere in the world says plastic bags are the greenest option, then why are they being banned? Does that make sense to you?
I was surprised to find that our traditional PE and PP bags are far greener than the alternatives that are being thrust upon us. That means that the bans being implemented are actually harming our environment. Plastic bags are being taxed to discourage use. That may be a nice source of revenue, but it is counterproductive. This is exactly why we need facts before we act. Without hard data, we end up doing harm instead of good. Governments, companies and environmental groups have not done their due diligence. They are making statements and taking policy decisions without checking the data first.
This opened my eyes and showed me that it is not safe to trust what we’ve been told. We have to stop parroting the same old sound-bites and headlines from articles written by people who did not spend the time to check the veracity of their words. I was also deeply disappointed with the so-called environmental groups. I had assumed that they had done their homework and given us good advice. After all, they collect millions in donations and have had decades to find the best path forward. How is it that with all that funding they did not find ten minutes to type “LCA plastic bag” into Google? Why are they advocating bans that harm our planet? It makes me seriously question their competence and motives.
What about other uses for plastics? What do the lifecycle studies show for other applications of plastic versus renewable materials? I went looking for more information and found LCAs done by the Bank of Canada and the Bank of England. Both showed that polypropylene plastic banknotes were far greener than cotton notes. In fact, after several days of searching, every LCA I have found shows plastics to be the best solution.
CNN featured news about the World’s first supermarket aisle free of plastic packaging. They touted the move to “new compostable bio-materials as well as traditional materials” such as glass, metal and cardboard.” That sounds admirable enough, but they presented no evidence that what they had done was actually green. So, is their idea environmentally sound or just a publicity stunt? The only way to be sure is to look for the evidence.
A good starting point is a leaflet called Preventing Food Waste from the American Chemistry Council. It shows that plastics are incredibly good at protecting our food and preventing waste. The food is protected during transportation and then it helps prevent spoilage. Cucumbers last 11 days longer, bananas last 21 days longer and beef 26 days longer. They showed that good packaging can save many billions of dollars and millions of tons of food.
Here’s a statement from the conclusions of a detailed report called Plastics & Sustainability published by the American Chemistry Council.
“Plastic packaging has many properties that are vitally important for packaging applications, including lightweight, flexibility, durability, cushioning, and barrier properties, to name a few. This substitution analysis demonstrates that plastic packaging is also an efficient choice in terms of environmental impacts.”
“For the six packaging categories analyzed – caps and closures, beverage containers, stretch and shrink film, carrier bags, other rigid packaging, and other flexible packaging –14.4 million metric tonnes of plastic packaging were used in
the US in 2010. If other types of packaging were used to substitute US plastic packaging, more than 64 million metric tonnes of packaging would be required. The substitute packaging would result in significantly higher impacts for all results categories evaluated: total energy demand, expended energy, water consumption, solid waste by weight and by volume, global warming potential, acidification, eutrophication, smog formation, and ozone depletion, as shown previously…”
From this we can see that plastic packaging is by far the best solution for our environment. In fact, another study showed that plastic packaging also leads to enormous reductions in CO2 emissions because they help food stay fresh longer. Food production is a major cause of carbon dioxide production and plastic packaging greatly reduces CO2 even accounting for the carbon dioxide from plastic production.
For a review on the impacts of plastics, see this from Imperial College London – DOWNLOAD
When I first wrote about plastics and how the evidence showed them to be the greenest solution, most people were glad to see an article that supported by extensive data. Probably the biggest pushback was from people saying something like, “even if plastics are the greenest solution, what about the litter and the oceans”?
Of course, litter is a separate topic and I didn’t have the answers, so once again, I had to go looking for them. There is a surprising amount of information about litter. For example, the EPA in the US have collected extensive data on all waste since the 1960s. It’s available for download but there’s so much that I could not make any sense of it. I had to ask a professional Data Architect to make graphs so that we could see the trends.
What we see is that plastics waste grew rapidly at first, because it was new material. However, in the last couple of decades, the growth of plastic waste has slowed and now follows population growth. Population growth rate passed through a maximum many years ago and has been decelerating ever since. We can expect a waste generation to follow that trend.
Here is a quote from a peer-reviewed article written about this EPA data:
“A comparison of waste generation rates for each material category found in MSW reveals that plastics increased by nearly 84 times from 1960 to 2013 while total MSW increased only 2.9 times. The increase in plastic waste generation coincides with a decrease in glass and metal found in the MSW stream. In addition, calculating the material substitution rates for glass, metal and other materials with plastics in packaging and containers demonstrates an overall reduction by weight and by volume in MSW generation of approximately 58% over the same time period.”
This is in line with the other studies that found replacing plastics would lead to far more material usage, waste and environmental burden.
I just read a post on LinkedIn saying that 90% of plastic waste has never been recycled. That sounds dramatic, so I went to the EPA data to see what that number means in context. We find that 9% of plastic in the US is recycled compared to 5% of food waste, 34% of metal, 16% of wood, 15% of textiles, 67% of paper and 26% of glass. Why was only plastics mentioned in the post as though plastics were of special cause for concern? It is not productive to demonize plastics. Instead we should look at all the data to see that there is clearly huge room for improvement for all material types.
Plastics account for just 13% of all US household waste by weight and under 0.5% of total waste. Why is it then that people only talk about plastics waste? I have never in my life seen an article complaining about glass waste or metal waste. Why are people obsessed with <0.5% of our waste and disinterested in the rest? I think that there are several reasons. Firstly, plastics was something new and people saw its dramatic growth. Another reason is that much of the common plastic floats, so we can see it on the surface of the water. In contrast, metal and glass both sink. There are many sunken ships. The Titanic alone weighed over 50 000 tons but no-one talks about it in terms of ocean litter. In fact, it is common to intentionally scuttle ships in order to make for good diving sites. I have seen TV shows talking about how great sunken ships are in creating artificial coral reefs. The Gen. Hoyt S. Vandenberg, a massive World War II ship weighing 17 000 tons was intentionally scuttled for divers. Why is it that metal is treated as a delight to nature and plastics are vilified? It’s something to think about. I don’t think any kind of ocean litter is good and we should treat it all with equal disdain. It has been estimated that the Great Pacific Garbage Patch weighs 80 000 tons. That’s the same as the Titanic and the Gen. Hoyt S. Vandenberg combined. The patch is in the news all the time but the ships are not.
In looking for data on litter in the USA, I found the website of Keep America Beautiful who have studies and reported on this topic for decades. They actually study litter as it happens, noting the circumstances and whether or not the act was intentional. Here is a quote from their report:
Litter is primarily the result of individual behaviors.
What does this mean? The conclusion is clear. People are responsible for dropping the litter and 81% of the time, it’s intentional. You can literally watch them do it on purpose. Of course, these are the same people blaming plastics for the litter problem. They are not honest enough to look themselves in the mirror and admit where the real problem lies. Instead, they drop the litter on purpose and then blame the litter. What is the consequence? People are pushing to ban plastics, conclusively proven to be the greenest option, when the problem lies with human behavior. As mentioned elsewhere, replacing plastics with other materials does about 4x more harm than the plastic does and creates 4x more litter as well. Is that what you want? How do we change human behaviour? First, education for children. For adults I would suggest heavy fines that escalate with every violation. Fines combined with humiliating punishment such as having to clean up trash in your own street in front of your neighbours while wearing a fluorescent orange vest saying “Litterer” would probably be highly effective.
As mentioned, plastics are 13% of solid municipal waste. It has also been pointed out that building rubble is a huge contributor to solid waste but is not included in municipal waste numbers. The book Rubbish! states that paper, cardboard and rubble account for 50% of all solids in a landfill. This means that plastics are about 10% of the solids in a landfill. What other waste sources are there? Well, industrial waste is not included in the EPA numbers. How much industrial waste is there? I was shocked to learn that although no-one has a really solid number, it is generally said that municipal waste is about 3% of all waste whereas industrial waste accounts for the other 97%. This means that plastic waste is less than 0.5% of all waste. Why are we focusing 100% of our attention and money on plastics? While reducing waste is a worthy goal, we will not make any real impact as long as we keep ignoring the other 99% of the problem!
So, we have learnt a lot. Let’s look back and summarize what all of this new information means.
I hope that you found this page of some use. Some people will be happy to see so much solid, independent data. Other people will remain skeptical. If you are skeptical, I would ask you to try and remember how you formed the view you have now. Was it from some LinkedIn headline, YouTube video or FaceBook rant? If it was from an online article, did they quote a multitude of peer-reviewed scientific studies as I have done? Remember, what you read online is just an opinion unless it is backed by data. What you read here is the truth because it is supported by a great number of independent studies from around the world.
Disclaimer: I have made every effort to ensure that the content provided here is accurate. Please inform me if you find an error and send me any data you think should be included. It is the reader’s responsibility to look at all the evidence available here and form their own opinion.
Role of plastics in decoupling municipal solid waste and economic growth in the U.S.
D.A. Tsiamis, M. Torres, M. J. Castaldi, Waste Management 77, 147–155 (2018)
Life Cycle Impacts of Plastic Packaging Compared to Substitutes in the United States and Cananda –
Theoretical Substitution Analysis – Franklin Associates, A Division of Eastern Research Group 2018