How many times do we need to reuse reusable bags? 

The answer to what are the best replacements for single-use plastic bags is not straightforward. However, there’s one solution to tackle this problem, here is the deal: Reuse whatever reusable bags you have, as many times as you can. So how many times must we use them to compensate for their larger environmental impact? 

Credit: the Beijinger

Reusable bag’s lifespan assessments

There are a couple of indispensable factors to consider when determining a bag's environmental impact over its lifetime, including the material, its weight, the manufacturing process, and how it is disposed of.

A thin single-use plastic bag may seem like a good idea based on its effect on the climate, but a heavy-duty plastic shopping bag made of the same material as a traditional single-use plastic bag but twice as hefty has twice the environmental impact, unless it is reused more times. The key for heavy-duty plastic bags is to faithfully reuse them and dispose of them carefully so they don’t end up as plastic pollution.

In contrast to a single-use plastic bag, a thick and sturdy polypropylene bag (PP Woven Bag) must be used an estimated 10 to 20 times, while a slimmer but still reusable polyethylene (PE) bag must be used five to ten times, according to a report produced for the United Nations Environmental Programme in 2020.

On Tuesday, April 2, 2019, a plastic bottle washed ashore on the shore near Sandy Hook, New Jersey, the same day that the environmental organization Clean Ocean Action revealed that volunteers removed more than 450,000 pieces of trash off the state's coastline in 2018. 

How many times must a reusable bag be reused?

Credit: Bride Street Market

Scientists can usually provide a very simple advice after all of this data has been compiled: the number of times a specific bag should be reused in comparison to the typical supermarket plastic bag.

A 2018 Danish study, looking at the number of times a bag should be reused before being used as a bin liner and then discarded, found that:

• PP woven bags (most of the green reusable bags found at supermarkets) should be used 37 times

• Paper bags should be used 43 times

• Cotton bags should be used 7,100 times.

Another UK study, which only considered the climate change impact, found that to have lower global warming potential than single-use plastic bags:

• Paper bags should be used three times

• Low-density polyethylene bags (the thicker plastic bags commonly used in supermarkets) should be used four times

• Non-woven PP bags should be used 11 times

• Cotton bags should be used 131 times.

However, if a plastic bag is reused (even as a bin liner) the number of times an alternative needs to be used increases.

It's worth noting that, according to the 2018 Danish study, using organic cotton has a greater environmental impact than non-organic due to higher production costs. Our assumptions about what is environmentally friendly don't always stand up to scrutiny.

Reusable LDPE and polypropylene bags do have a lesser environmental impact than the typical plastic bags seen in supermarkets, according to a 2014 study conducted in the United States, but only if they are used frequently enough. According to this study, about 40% of customers used plastic bags because they had forgotten to carry their own reusable bags. Consequently, this increases the environmental impact of purchasing.

How many reusable bags do you actually need? 

The bags' volumes were equalized by the Danish researchers so that measurements could be done using the same amount of space (this meant that for some assessments it was necessary to consider the impact of two bags).

As with all matters environmental, it's essential that we have the right knowledge to make wise decisions. After looking at all this data, here are the things we should remember:

• Whatever bag type you use, use it as many times as possible
• Choose reusable bags made from recyclable materials.
• Avoid bags that have printing or decorations - these alone can add significantly to the environmental burden of the bag.
• Never allow a bag to become litter - recycle, reuse and repurpose your bags.

Source: Trevor Thornton, The Conversation

TLPPACKAGING FOR SHOPPING BAGS