New research from WMG at University of Warwick has found that the carbon footprint of collecting and refurbishing abandoned trolleys adds up to the equivalent of flying from London to New York and back twice!
"Thousands of shopping trolleys are reported as abandoned in the UK every year. When you multiply the carbon impact of retrieving each one, it becomes both significant and concerning," explains Neill Raath, Assistant Professor at WMG, University of Warwick, who led the research.
Despite supermarkets introducing a range of methods to stop shopping trolleys leaving their premises, including coin slots and wheel-locking mechanisms, over 520,000 are still reported as abandoned in the UK each year, according to global trolley and retail equipment manufacturer, Wanzl.
Supermarkets rely on commercial collection services, typically using diesel vans to survey suburban areas, to collect and return the trolleys. Researchers at WMG assessed the environmental impact in order to tally the full cost of abandoning a trolley.
Collecting versus manufacturing
The researchers analysed the environment impact of trolleys through their entire life cycle (from production to disposal including retrieval), focusing on abandoned trolley activity around the local area in Coventry (including the Cannon Park Shopping Centre and the University of Warwick campus).
Collection services reported collecting approximately thirty trolleys a week in the area, with an estimated one hundred trolleys a year sent for refurbishment via regalvanisation (a zinc coating process to prevent corrosion).
Across a Coventry trolley's lifecycle, collection counted for 1% of the environmental impact and refurbishment another 8%. Manufacturing the trolley is the costliest part of a trolley's life cycle, namely due to the construction of the steel frame.
Extrapolating this out to the most recent data of 520,000 abandoned trolleys in the UK in 2017, if we collected them all with vans it could emit the equivalent of 343 tonnes of CO₂ (the annual equivalent of driving eighty petrol cars). If we refurbished just 10% of these trolleys, it would almost double those emissions.
While that may sound bad, using commercial services to collect abandoned trolleys was more carbon efficient than losing them in service, and having to manufacture replacements.
Dr Raath said: "We found that one trolley would have to be collected 93 times by a diesel van to have the same environmental impact as manufacturing a new one."
Circular economy: A more sustainable solution
These results tell us that preventing trolley abandonment and keeping them in use for as long as possible should be a priority not just for supermarkets, but for the public as well.
It also reinforces the benefits of the circular-economy. If a trolley is abandoned, it is far better to collect and refurbish it, than to let it fall out of use and manufacture a new one. 92-99% of the environmental impact could be avoided this way.
Dr Raath added: "While it is unlikely that we can ever stop trolleys being abandoned, we hope that next time people see a trolley in an alley or park bush, they'll consider the environmental impact of letting it go unused."
Marc Radforth, from Wanzl added: "Wanzl is committed to reducing the impact of trolley abandonment on the environment, in part by offering services for retailers such as Trolleywise and Reviva. We are working collaboratively with retailers to continue to look for ways to further reduce trolley loss and trolley replacement requirements."
