The debate over the banning of plastic bags gets a lot of attention in some countries.
In this guide, we look at the different factors that might be considered on either side of the debate.
We also look at whether they are better or worse than other types of bags.
Summary – Should We Ban Plastic Bags?
It depends …
Surprisingly, in some studies and across a wide range of environmental (and human toxicity) indicators, regular LDPE plastic shopping bags have the lowest and most beneficial impact when considering bag production and disposal, compared to others types of bags like recycled plastic, cotton, organic cotton, paper (bleached and unbleached), and composite bags (made with jute).
For some individual indicators, like human toxicity impact, paper and composite bags can be equally as low impact.
So, you have to isolate a particular indicator you are measuring for bag impact when talking about impact of a bag material
These studies admittedly don’t take into account some key factors like some types plastic pollution in the ocean and on land, littering of plastic, and economic factors to do with plastic production and disposal, just to name a few
In addition to environmental and specific types of human toxicity indicators that these studies might measure, economic (profitability, economic feasibility, job creation etc.), human health, practical, and technological indicators could be measured for impact by each material
As a good rule of thumb for eco friendliness alone when it comes to bags – individuals might look at going zero waste where they can, trying not to buy new bags, re-using a bag as many times as possible before disposing of it, while also using it as a bin/waste liner (or for some other alternate use) where it can’t be used to carry items anymore.
Recycling and incineration appear to be desirable disposal options for some types of bag materials when a bag can’t be used anymore
When it comes to the footprint an individual is leaving on society, more important considerations than the bag you choose might be what you put in it … i.e. how and what are you consuming, how often, and what footprint are you leaving from your consumption patterns in terms of how you live your life.
The type of bag material you use might not be as significant as these other types of choices – what we eat, how and what we drive, and how big and how well insulated our houses are might be the most important eco related lifestyle choices we make as opposed to the type of bag we use (using less bags and re-using existing bags more often might also be more important than the material of bag)
So, plastic bags appear to have their pros and cons, depending on many variables and factors and what specific indicators you are measuring
Whether we ban plastic bags entirely or not probably requires us to look more deeply at their impact in terms litter and plastic pollution in the ocean, impact on wildlife, impact on wildlife and ecosystems, impact on other human health measurables, and given local city conditions (such as the production and waste management technology and processes in a given city)
Other solutions to banning plastic bags might exist such as significantly increasing the price of them to discourage people from buying them when they don’t absolutely need them
Plastic bags are among some of the most commonly picked up items on land and on beaches during clean ups, so it makes sense that reducing their numbers through lower usage rates will also reduce litter pollution problems
Lifecycle Assessments On Plastic Bags
This is a Danish lifecycle assessment on different materials of grocery carrier bags.
The key methodology and findings summary parts of the assessment report are available on pages 13 to 19.
Some of the key considerations from the assessment/report are (paraphrased or selected by us):
Types Of Bags Studied
Different types of plastic bags, recycled plastic bags, paper bags, cotton bags, organic cotton bags, composite bags with jute, PP and cotton (see page 13 for bag types)
Environmental (& Human Health) Impacts Assessed
Climate change, ozone depletion, human toxicity cancer and non-cancer effects, photochemical ozone formation, ionizing radiation, particulate matter, terrestrial acidification, terrestrial eutrophication, marine eutrophication, freshwater eutrophication, ecosystem toxicity, resource depletion, fossil and abiotic, and depletion of water resource (see pages 14 and 15 for environmental impacts assessed) [characterisation description and unit of measurement for each impact available on page 39 in Table 5 – characterized mainly according to LCIA methods]
Preferable Disposal Method For Bags
Re-using a bag as many times as possible is usually the best first option, followed by using it as a bin liner.
Recycling can benefit some types of heavy plastic bags.
Otherwise, incineration is usually a good option when re-use is not feasible or possible (see page 16 for more info)
Bag That Provides Lowest Environmental Impact
In regards to production and disposal, plastic LDPE bags have the lowest impact across the whole range of environmental and human toxicity indicators.
For specific indicators, such as human toxicity, paper, composite and plastic PP bags can also be lowest impact. (see pages 16 and 17 for more info)
How Many Times Bags Have To Be Re-Used To Have The Same Impact As Each Other According To The Impacts Assessed
Regular LDPE plastic bags are the benchmark when used as a waste bag.
Recycled LDPE has to be used 2 times and used as a bin bag to match the impact across all indicators, recycled PET 84 times and recycled, unbleached paper 43 times and re-used as waste bag or incinerated, conventional cotton 7100 times and re-used as waste bag or incinerated, organic cotton 20000 times and re-used as waste bag or incinerated, and composite bags 870 times and re-used as waste bag or incinerated (see pages 16, 17 and 18 for more info)
Some of the potential limitations of the study may have been:
The results are specific to Denmark (so, the results may be different in some ways in other countries where plastic and other materials is produced, and disposed of differently).
The results may also change if certain assumptions in the report change
Key factors such as littering of plastic, the breakdown of plastic into micro plastics and non plastics, the impact of plastic in oceans, soil, rivers, and water and food supplies, the impact of plastic on wildlife and ecosystems, and economic feasibility of certain stages of the plastic lifecycle, were not considered in the report as far as we can tell ourselves.
From page 24 of the report: “The present study only considers carrier bags available for purchase in Danish supermarkets in 2017. Small very lightweight plastic carrier bags, which are available in Danish supermarkets free of charge as primary packaging for loose food, were excluded from the scope of this study, since they were not included in the 94/62/EC measures. This study does not include the assessment of other types of carriers, such as personal bags or bags provided by other retailers. The report does not consider behavioural changes or consequences of introducing further economic measures. The study does not take into account economic consequences for retailers and carrier bag producers. The environmental assessment does not take into account the effects of littering.”
Other life-cycle assessment studies/reports on plastic bags and other bag types:
UK study measuring global warming impact of plastic bag types (assets.publishing.service.gov.uk)
US study measuring global warming impact of bags (tigerprints.clemson.edu)
What we see from these studies is that there are many variables and factors to consider such as the material the bag is made of, assumptions made on the size, weight and consumer behavior associated with the bag, assumptions made on the material of each bag, production and disposal of materials and waste in a given country, whether the bag has bleaching and printing on it, how many times the bag is re-used, over what time period the bag is used without buying new bags, whether the bag is used as a waste liner or not, transport and delivery of the bags, + much more.
More Relevant Information On Plastic Bags & Their Potential Impact
[what is not considered in the above studies apart from plastic litter is that] Plastic bags do not biodegrade and are stuffing the oceans, marine life, and our food supply with plastic bits. [If we take marine litter into account … plastic bags are almost certainly the worst]
[A problem with organic cotton is that it is assumed to have lower yields, and therefore is assumed to have higher resource inputs for the same yield]
[Even accounting for the benefits of organic cotton] conventional cotton can out on top [across many environmental indicators for the bag life cycle assessment]
[The problem with textiles like cotton is there is] very little infrastructure [that] exists for textile recycling.
… replacing plastic bags with paper ones will surely have deleterious side-effects like increasing deforestation. Making a paper bag also requires more energy and water than making a plastic bag, so for other environmental considerations besides litter, paper products may be worse than plastic ones
As the Verge [Verge article listed in the resources below] pointed out last year, regardless of the bag you choose, what is likely of vastly greater importance is what you choose to put in it and how you carry it around: Eating less meat, cycling or walking to the store, and buying locally-made grocery products are all likely to make a bigger difference in lowering your personal contribution to environmental problems.
The simplest advice for individuals seems to be this: Whatever you have in your house now—be it a pile of cotton totes, or a jumble of plastic bags—don’t throw them out. Keep using them until they fall apart. Whatever the material, use it as a garbage bag once you can’t use it for other purposes any more. And whatever you do, try not to buy new ones.
Plus, knowing how many resources it takes to make a piece of cotton, treat fabric items in your home like infinitely reusable resources worth their carbon-mitigating weight in gold. Find new uses for old clothes, use textiles until they wear out, and when you want something new, buy vintage.
Plastic bags come out on the right side of the equation [compared to paper bags] on everything except the recycling side
[When choosing between plastic and paper bags …] Neither option is best. The better option is to bring your own
[Considering what to do with bags after they can no longer be used or re-used is an important question]
[A good solution to the plastic bag problem if there is one is to make them more expensive or tax them more heavily – so people are encouraged not to use them unless they really need them]
[More important eco lifestyle choices than the types of bags we use might be what we drive, what we eat, and how big our house is an how well insulated it is]
Can Plastic Bags Be Recycled As A Soft Plastic?
In many cities, soft plastics like plastic bags can’t be recycled because of issues such as contaminating other plastics, and getting stuck in recycling conveyor belts and other machinery.
However, there are some private services in some cities that offer soft plastic recycling, and turn it into recycled material that can be used for park benches, decking, bollards and more (ecobin.com.au).
You will have to do an internet search though for [soft plastic recycling ‘insert city name’].
Plastic Bag Pollution
Plastic bags are among the littered items most commonly found during clean ups on land and on beaches and coast lines