For many years, cloth bags have been seen as an environmentally-friendly alternative to the ubiquitous plastic bags found at shops around the world. Despite their popularity, a recent study completed by the government of Denmark has reached some surprising conclusions about the relative impacts of cloth, reusable plastic, and single-use plastic bags.

The study attempted to define the environmental impact of different types of bags by considering factors such as the impact of manufacturing on climate change, water use, ozone depletion, air pollution, and toxicity.

The conclusions, presented clearly in a diagram in this article, might be surprising to some. The researchers decided to present the results as a comparison of relative environmental impacts. To do this, they calculated the number of times a reusable bag would need to be used to have the same impact per use as one standard single-use polyethylene bag.

Unexpected Results

The results are striking: a cotton bag would need to be reused 7,100 times before it had less of an impact than a plastic bag. In other words, one cotton tote bag has the same environmental impact as 7,100 reusable polyethylene bag. Organic cotton comes in even worse: one bag is equivalent to about 20,000 single use plastic bags.

These findings should, however, be taken with a grain of salt. Critically, the study did not consider plastic waste released into the environment. This is likely because we still have a poor understanding of the long-term effects of plastics on the natural environment, making such effects hard to quantify.

Study Has Implications for Ideal Grocery Shopping Habits

The most important message we can take from this study is that the manufacturing and production of durable goods has an unescapable environmental impact.

The authors of the article cited above have two important pieces of advice for people hoping to reduce their environmental impact:

The first is that any item that has already been manufactured – including plastic bags, reusable bags, cardboard boxes, and other containers – should be reused as much as possible. Before you go out and buy a set of plastic bags, it would be best to look around your house and consider reusing items you already have.

The second piece of advice, which is striking, is that what you put in the bag has a much larger environmental impact then the bag itself. Reducing consumption of meat and items shipped over vast distances is still the most effective way to reduce the environmental impact of shopping for groceries.