Single-use plastic bags ‘greener than cotton totes’

SINGLE-USE plastic bags could be better for the environment than cotton totes reused 50 times, a study has found.

Scientists at Nanyang Technological University in Singapore found that in the country’s waste system, the water and energy consumption that goes into cotton and paper bags made them worse for the climate than plastic.

The best option was a long-life plastic bag used at least 50 times, followed by the single-use plastic bag and a cotton bag used 50 times, said the study, published in the Journal of Cleaner Production.

Most of Singapore’s rubbish is collected from home and incinerated, meaning the risk to the oceans from waste plastic is minimised, the authors said, adding that the conclusions would be different for countries that biodegraded or recycled more of their waste.

The authors added that strict anti-littering measures in Singapore also reduced the likelihood that plastic would find its way into rivers and the ocean, where it is harmful to wildlife.

Grzegorz Lisak, director of the residues and resource reclamation centre at the Nanyang environment and water institute, said the relative benefits of single-use plastic bags were “surprising”.

The authors examined five varieties of bag, concluding that single-use paper bags were the worst option in terms of global warming impact, with reusable plastic the least detrimental.

Switching to paper or cloth from plastic “would increase the environmental footprint resulting in heightened negative effects such as global warming and eco-toxicity potentials”.

Prof Lisak said: “Our main message is that reusable plastic bags are the best option, provided that they are reused many times – over 50 times to be precise.

“However, one surprising conclusion is that, in our model, in a single-use case, plastic bags, if treated properly afterwards, are less environmentally detrimental than the other types of bags in this study.”

Prof Pauline Deutz, an expert in circular economies at the University of Hull, said that while some conclusions were specifically applicable to Singapore, the study showed the importance of reusing bags as much as possible because of the extra resources used to make them.

“It is how you use the bag that counts more than what the bag is made of,” she said.

The UK is also incinerating a growing amount of its waste. In the financial year to 2019, 44 per cent of household waste was incinerated and more than the 43 per cent sent to be recycled.