Here's how many times you have to use a tote bag for it to actually be environmentally friendly

woman with tote bag Tote bags have become so ubiquitous that even men are carrying them around.

Retailers started pushing tote bags as early as 2007 to promote sustainability, on the assumption that reusing the same bag can help curb customers' carbon footprints.

Counties and cities around the US —most notably San Francisco — have even started to charge customers for bags to encourage them to bring reusable ones. Lawmakers in New York's Suffolk County approved a five-cent bag fee on September 7.

But tote bags have a high carbon footprint, too. In fact, reusing a single plastic bag three times has the same environmental impact as using a cotton tote bag 393 times.

A study on grocery carrier bags conducted by the UK's Environment Agency, which was published in 2011, looked at seven different types of bags: paper, cotton, a biodegradable bag made from starch and polyester polymers, and four bags of varying polyethylene densities.

Those four polyethylene bags included sturdy tote bags, a standard grocery store bag made of high-density polyethylene (HDPE), and lower density reusable tote bags (the kind you can commonly buy at the checkout of your local grocery chain for a dollar).

plastic bags

The study found that the production of tote bags commonly marketed as sustainable actually had an environmental impact many times larger than that of a standard plastic HDPE bag. Because of the resources needed to produce the materials for cotton totes, the study measured a cotton bag's total footprint (including growing, manufacturing, and transportation) at a whopping 598.6 lbs of CO2. The standard HDPE bag, on the other hand, emits 3.48 lbs.

"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 fertilizers used during the growth of the cotton," the study says.

The standard HDPE bags had less impact on the environment because fewer materials are needed to make them. Production of HDPE bags also created approximately a quarter the amount of waste and required just over half the electricity needed to manufacture cotton totes.

The study found that the most sustainable way to deal with plastic bags wasn't necessarily to recycle them (in the US, you have to drop bags at a specialized recycling program to do that). Instead, you should reuse them as many times as possible before recycling.

So if you're still set on using a cotton tote, make good on your purchase by using it for enough years to realize its sustainability potential. After all, that's what it's designed for.

Join the conversation about this story »

NOW WATCH: An architect figured out how to build houses from plastic waste