There is a global consensus to combat the problem of plastic pollution. On March 2, 2022, at the Fifth United Nations Environment Assembly, leaders from 175 countries, ministers of the environment and other participants adopted a historic resolution. The aim of the resolution is to end plastic pollution and to reach a legally binding international agreement by 2024. This upcoming agreement is being hailed as a "global ban on plastic.
We are calling for the fight against plastic pollution at the same time, need to consider is that the best alternative to single-use plastic bags is what? Non-woven bags, or paper bags?
Non-woven bags are much sturdier than disposable plastic bags, and we have to recycle them several times to compensate for their environmental impact, yet in most cases, people don't use them to their full potential.
At the same time, another seemingly unmistakable paper packaging is taking off, even if such paper bags are not completely biodegradable, as it seems that most of them also need to be covered with a layer of traditional plastic film in order to obtain the effect of waterproof and oil-resistant.
Therefore, we need a "life cycle assessment" study to help us understand the impact of common types of reusable bags. The above-mentioned "global plastic ban" also covers the entire life cycle of plastics, including their production, design, recycling and disposal.
1、Life cycle assessment
Life cycle assessment considers a wide range of factors, including raw materials, manufacturing, transportation, and final disposal. By looking at all of these factors, researchers calculate greenhouse gas emissions, waste disposal, water and energy consumption, and various other impacts. To complicate matters further, if you choose a plastic bag, is it made from virgin or recycled plastic? Even if the bag is recycled, transportation is an issue - where is it made? Printing on the bags also adds to the environmental burden. Finally, what happens to the bags when they can no longer be used? Are they recycled, reused as garbage bags, or thrown away immediately?
2、How many times must a bag be reused?
Once all this information has been distilled, scientists can often provide a fairly straightforward guide: the number of times a bag should be reused as an alternative compared to the standard supermarket plastic bag.
A 2018 Danish study that looked at the number of times a plastic bag should be reused before being used as a garbage bag and then discarded found that
1. Non-woven bags should be used 37 times
2. Paper bags should be used 43 times
3. Cotton bags should be used 7100 times
Another British study found that considering only the effects of climate change, its global warming potential was lower compared to that of single-use plastic bags.
1. Paper bags should be used 3 times
2. Low-density polyethylene bags (thicker plastic bags commonly used in supermarkets) should be used 4 times
3. Non-woven polypropylene bags should be used 11 times
4. Cotton bags should be used 131 times
If the non-woven bag is used only once, then the energy consumption of a single non-woven bag is 17.8 times that of a disposable plastic bag, and carbon emissions are 16.7 times that of a disposable plastic bag. Assuming that the use of non-woven bags can reach more than a year (measured once / week), the energy consumption of non-woven bags is only 34% of disposable plastic bags, emissions are 32% of disposable plastic bags. Therefore, non-woven bags need to be reused for a long time to achieve the purpose of environmental protection, otherwise it will cause greater environmental pollution.
Environmental Influencing Factors | Disposable plastic shopping bags | Non-woven (use 1 time) |
Material consumption (kg) | 3.12 | 24.96 |
Energy consumption (kg standard coal) | 7.17 | 127.64 |
Greenhouse gas emissions (kg CO2) | 6.08 | 101.92 |
Solid waste (g) | 4.6 | 34.3 |
A 2014 study conducted in the United States found that reusable LDPE and polypropylene nonwoven bags do have less of an environmental impact than the plastic bags commonly found in supermarkets, but only if they are reused enough times. This study found that about 40 percent of shoppers forget to bring reusable bags and therefore end up using plastic bags. This adds to the environmental burden of shopping.
A final consideration is how many bags you need. The Danish researchers equalized the volume of the bags so that they were evaluated on the same volume of space (which means that for some evaluations it was necessary to consider the effect of two bags). As with all environmental issues, it is important that we have the right knowledge to make informed decisions. After reviewing all this data, here are the things I want you to keep in mind.
1. Whichever type of bag you use, use as many as possible
2. Choose bags made from recyclable materials
3. Avoid printed or decorated bags, which alone can significantly increase the environmental burden of bags
4. Never let bags become garbage, recycle, reuse and repurpose your bags
