A new study has suggested that online shopping for books, clothes, CDs and DVDs is 24 times greener than taking the car to the shops and seven times greener than taking the bus.
According to a report in The Scotsman, researchers at the Heriot-Watt University, Scotland, carried out the study.
The researchers compared the carbon footprint of a typical trip from a local delivery depot with that of average shopping trips by car and by bus, and found home deliveries involved a much lower level of carbon emissions.
The work, which assumes only one item was bought per trip, focused on the last stage of the retail process when goods are delivered to the home or customers travel to the shops to collect them in person.
The team from the Logistics Research Centre at the university found that a typical van-based home delivery produces 181g of CO2, compared with 1,265g for a bus trip and 4,274g for a trip by car.
It means a shopper would have to buy 24 items when going by car or seven items when going by bus to equal the lower level of carbon emissions created by having one item delivered by van.
Professor Alan McKinnon, director of the Logistics Research Centre, and one of the authors of the study, said that the findings showed that online shopping for single items could be a great deal "greener" than a conventional trip to the shops.
"Some online retailers were claiming that if you shopped online you were doing something good for the environment - but until now we lacked hard evidence," he said.
"The results suggest that is true. What this shows is if you are buying small non-food items, it is better for someone to get them delivered than to go to the shops by car or bus," he added.
Professor McKinnon said that he hoped the findings would encourage shoppers to think about the environmental impact of their shopping choices.