Science is Important

If we are to protect the environment and stop climate change, we must be guided by science and not by uninformed decisions by policymakers based on unscientific, feel-good populist views. Everyone wants to look green, but being truly green begins with science so we can have policies that are effective and really help the environment.

The way policymakers are making their decisions now will end up hurting the environment and have a number of negative unintended consequences.
Isn’t it better to listen to science?

Why would any policy maker want to ban plastic bags if it hurts the environment, especially when there are betters ways to manage all bags without bans?

There are many answers to this question from political expediency, a lack of knowledge, a distrust of science, a desire to garner votes, ideology and emotion.

Now is the time that policymakers listen to the experts and scientists, whether it is their own staff or research by reputable governments of Great Britain, Denmark or Quebec if we are to address our environmental challenges.

Independent third-party scientific peer reviewed research has been undertaken by the environmental agencies of these governments comparing plastic shopping bags to all alternatives, possible substitutes.

Studies show that the plastic bag is the best bag environmentally, has the lowest carbon footprint and the lowest global warming potential.

This independent, impartial, third party research is an effort by government and scientists to identify the best policies on bags to protect the environment and economy. This research  shows that paper bags emit 4 to 7 times more carbon into the environment acidifying and warming our oceans; that reusable bags must be reused at a minimum 11 times to match the environmental impact of a plastic bag used just once.  On top of that, reusable bags are not recyclable because they are made from many different types of materials which makes it too expensive to recycle them.

These studies show that there are no silver bullets – no easy answers on bag policies and all bags have environmental and economic impacts. The question is which bag has the lowest impact on the environment and the science proves that is the plastic shopping bag. Science also shows that bag bans have unintended negative environmental consequences and that the best way forward is public education on the 3R’s to change how consumer use bags.

Here's the Science

Compared to all others plastics shopping bags are the best bag to use environmentally

The independent, cold facts provide an important guide to the best way to safeguard the planet.

Here’s what the governments of the U.K., Quebec, and Denmark found when they applied the science in what are called Life Cycle Analyses (LCAs). The Americans have done a number of studies too with the same results. The links to those studies are listed below.

Topline Findings

These government Life Cycle Analyses (LCAs) compared plastic shopping bags to substitutes.

All LCAs show that the thin 17 micron plastic shopping bag is the best bag on the market environmentally. The conventional plastic bag has the lowest carbon footprint; has the lowest environmental impacts of any other bag on the market. 

The Quebec Government LCA Recyc Quebec In Brief – January 2018

Environmental and Economic Highlights of the Results of the Life Cycle Assessment of Shopping Bags

Click here for English Highlights Report

Click here for English Full Report

The Quebec Government’s Life Cycle Assessment (LCA) compared the environmental impact of all shopping bags available in Quebec in order to determine which bag has the lowest carbon footprint using North American data. The LCA was conducted by the International Reference Centre for the Life Cycle of Products, Processes and Services (CIRAIG), affiliated with Polytechnique Montréal.

The LCA showed beyond a shadow of a doubt that the plastic shopping bag is the best bag environmentally and economically.

Three key findings:

  1. The conventional plastic bag is not a single-use bag, but a multiple-use, multiple-purpose bag. The conventional plastic bag has a 77% reuse rate in Canada. Only 23% of the bags are single-use, and these bags can be recycled.
  2. It found that reusable bags have a much larger carbon footprint because they are heavier bags using more material. And reusable bags must be reused multiple times to match the much lower environmental impact of the conventional plastic bag used just once.
  3. Paper bags have a much higher carbon footprint.  The paper bag is the least performing bag with 4 to 28 times greater potential impact on the environment than the conventional plastic bag.

According to the Quebec Government LCA, the Polypropylene (PP) woven and PP non-woven reusable bags need an equivalent number of reuses to equal the thin plastic bag ranging from 16 to 98 and 11 to 59 times, respectively, depending on the scenario and environmental indicator.  The report concludes that:

No alternative to banning plastic bags offers an environmental benefit. ... In this context, banning [thin HDPE bags] would not be advantageous.  

Denmark Government LCA Ministry of Environment and Food In Brief – February 2018

Life Cycle Assessment of grocery carrier bags

Click here for Denmark Report

The Government of Denmark LCA of grocery carrier bags found that conventional plastic shopping bags have the lowest environmental impact of all bags in their marketplace and that reusable bags have to be reused multiple times to provide the same environmental performance of the average conventional LDPE carry bag reused as a waste bin bag before incineration.

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 even when not considering reuse.

This study looked at 16 different bags. It found that the minimum number of reusable bag reuses needed to equal the environmental impact of thin plastic shopping bag used just once was very high:

  • a non-woven PP reusable bag needs to be reused 52 times;
  • a woven PP reusable bag needs to be reused 45 times;
  • a recycled PET reusable bag needs to be reused 84 times;
  • a polyester PET reusable bag 35 times;
  • an unbleached paper bag 43 times, and
  • organic cotton reusable bag an astounding 2,000 times.

U.K. Government LCA Environment Agency in Brief

Life cycle assessment of supermarket carrier bags: a review of the bags available in 2006

Click here for U.K. Study

 The study found that the conventional plastic shopping bag (HDPE) outperformed all alternatives, even reusable bags, on environmental performance. Conventional plastic bags have a much lower global warming potential. Heavier, sturdier reusable bags of all materials have a higher global warming potential.

Reusable bags are much more resource-intensive increasing their negative environmental impact. For example, the production of cotton with its heavy pesticide and water use has a negative impact on the environmental benefit of cotton bags. The consequence is that a cotton reusable bag has to be reused 131 times to be as good environmentally as a plastic shopping bag used just once.

  • Non-woven polypropylene bags would have to be reused 11 times to match environmentally the conventional thin bag used just once.
  • Paper bags would have to be reused three times to lower their global warming potential to match that of a conventional HDPE plastic shopping bag being used just once.

Amount of Primary Use of Alternatives to Match the HDPE Conventional Bag Environmental Performance With or Without Secondary Reuse of the HDPE Bag

Type of Carrier Bag HDPE Bag
(No Secondary Reuse)
HDPE Bag
(40.3% reused as kitchen catchers)
HDPE Bag
(100% reused as kitchen catchers)
HDPE Bag
(reused 3 times)
Plastic Bag 1 2 2 3
Paper Bag 3 4 7 9
LDPE Bag 4 5 9 12
Non-woven PP Bag 11 14 26 33
Cotton Bag 131 173 327 393