Five years ago, Kenya banned single-use plastics in protected areas including national parks, beaches, forests and conservation areas.
The move by the Ministry of Environment and Forestry, which was applauded globally, was meant to set the agenda for sustainable waste management and to protect the environment.
Recently, however, there has been debate on whether paper bags used in supermarkets and grocery stores are more or less harmful than plastic bags.
Lovers of paper bags have argued that they are good because they are biodegradable, while plastic lovers have argued that plastics are better because they are reusable.
But left undiscussed is what between the two is more eco-friendly. The Columbia Climate School says a life cycle analysis is needed to understand the impacts and benefits of each bag. This analysis focuses on how much energy is used and the impacts a product is responsible for at every stage of its life, which includes extracting raw materials, refining them, manufacturing, shipment, transportation and distribution, use and reuse, recycling and disposal.
“Life cycle studies done in Europe and North America have determined that, overall, plastic bags are better for the environment than paper or reusable bags unless the latter are used many times. Most, however, did not consider the problem of litter, which we know is a major drawback of plastic bags,” the school says.
While the extraction of natural gas and petroleum to make plastics requires a lot of energy, refining them also needs a lot more energy, it says.
Another study conducted in 2005 by the Scottish government found that manufacturing paper bags consumes 10 per cent more energy than manufacturing plastic bags, and that it uses four times more water and emits more than three times the amount of greenhouse gases. The study also stated that it generates 14 times more water pollution.
Seven studies conducted in 2020 by the United Nations Environment Programme (UNEP) concluded that the type of material and weight of a shopping bag are important when determining a bag’s impact on the environment.
A bag with the same material but double the weight has double the impact, unless it is reused more times or used to carry more goods.
“The number of times a bag is used directly influences its environmental impacts. For instance, if a bag is used for shopping twice instead of once, it has only half the environmental impact per shopping round,” UNEP says.
“The technology and material/energy use of production processes influence the impact of bags. For example, the climate impact of paper bags varies greatly, depending on what fuel is used in the pulp and paper production.”
And even though the studies praised paper bags for causing less littering to the environment and providing nutrients to plants at the end of their life cycle, they noted that they can only be better if the paper mills use renewable fuel, the paper bags are reused multiple times, and/or the waste bags are incinerated rather than deposited in landfills.
“Biodegradable bags decompose and contribute less to the impacts of littering, compared to conventional single use paper bags; however, results indicate they might be the worst option when it comes to climate impacts, acidification, eutrophication, and toxic emissions. The waste-management process also influences the environmental impact of bags,” UNEP said.
It adds: “Paper bags that end up in landfills cause emissions of methane with high climate change effects, while plastic bags are relatively inert. On the other hand, incineration of used plastic bags affects the climate through emissions of fossil carbon dioxide, while the carbon dioxide emitted from incineration of paper bags is part of the natural carbon cycle.
“The environmental impacts of biodegradable bags are reduced if the bags are composted, while most other bags benefit from material recycling.”
Touted as the best option because they are degradable and renewable, strong and reusable, cotton bags have also been shown to take significant energy in production and processing.
From the point of harvesting, cotton is taken to cotton mills to produce cotton threads that can be used to make fabric, which then undergoes a chemical procedure and bleaching.
Spinning and weaving requires a lot of energy, while washing, bleaching, dyeing and printing requires large amounts of water and electricity.
Just like paper bags require felling of trees for production, cotton bags require large masses of land for production, which is further complicated when chemical fertilisers are used.
“The use and production of fertiliser contribute significantly to eutrophication. Harvesting, processing, and transporting cotton to market all require large amounts of energy; and since cotton totes are heavy and bulky, they cost more to ship,” the Columbia Climate School says.
“In addition, they are difficult to recycle … As a result, a cotton bag needs to be used 7,100 times to equal the environmental profile of a plastic bag.”
It adds: “Generally speaking, bags that are intended to last longer are made of heavier materials, so they use more resources in production and therefore have greater environmental impacts.
“To equal the relatively low global warming impact of plastic bags, paper and cotton bags need to be used many times; however, it’s unlikely that either could survive long enough to be reused enough times to equal the plastic bag’s lower impact.
“Ultimately, the single use of any bag is the worst possible choice. The key to reducing your environmental impact is to use whatever bags you have around the house as many times and in as many ways as possible.”
This fact check was produced by the Daily Nation with support from Code for Africa’s PesaCheck, the International Fact Checking Network, and the African Fact Checking Alliance Network.
