Scientists at Nanyang University of Technology (NTU) have found that plastic bags are more environmentally friendly than paper and cotton bags, contrary to popular belief.
The research team said this is true in cities and countries such as Singapore, with densely populated metropolitan areas, where waste is eventually incinerated.
NTU scientists they came to this conclusion after conducting a life cycle analysis of five types of bags to assess their impact on the environment associated with production, distribution, transport, waste collection, treatment and end-of-life disposal.
Reusable, non-woven polypropylene plastic bags were the most environmentally friendly option, followed by disposable high-density polyethylene plastic bags.
Assistant Professor Grzegorz Lisak, who led the research, said the discovery that disposable plastic bags – treated properly – were less harmful to the environment was “surprising”.
Plastic is environmentally friendly, if you reuse it enough.
“It is essential to assess the case-by-case implications for the treatment of plastic waste,” said the director of the Waste and Resource Recovery Center at the Nanyang Environmental and Water Research Institute.
Reusable plastic bags must be reused four times to offset the emissions created by the production process of a single-use plastic bag.
“Our main message is that reusable plastic bags are the best option, provided they are reused many times.”
“In a well-closed and well-structured metropolitan waste management system with incineration treatment, the use of plastic bags may be the best option currently available, provided that there is no significant discharge of waste into the environment,” he added. Lisak.
Paper has harmful consequences for the environment
The study also found that the global warming potential of kraft paper bags is 80 times higher than that of reusable plastic bags. Disposable plastic bags and bags made of cotton have an ecological footprint 10 times larger than those made from reusable plastic.
This can be explained by the fact that in the process of making cotton and kraft paper bags, large amounts of water and natural resources are needed, which creates a greater ecological footprint.
In places like Singapore, where waste is incinerated, the timing of biodegradation of paper, cotton and other biodegradable materials is irrelevant. Such bags are suitable for countries that use landfills and regions with higher landfills in the wild, the study said. However, the scientists said that these bags could be greener in the future, improving their production method, optimizing the use of resources and following sustainable practices.
The team recommended the full use of reusable plastic bags to reduce the consumption of disposable plastic bags. Based on 2018 statistics, halving the consumption of disposable plastic food bags in Singapore could prevent more than 10 million kilograms of CO2 emissions per year.