Shoppers are particularly likely to buy more items than they intend to keep when buying clothes

Quite a few of us will have been panic-buying Christmas presents over the past week. Around a third of that last-minute shopping will be online, with many buyers shelling out for express delivery.

Besides the extra hit to the pocket, express delivery has an environmental cost. Rather than wait for more orders to fill up a van, online retailers often send out part-empty vans to deliver priority orders on time. That means more trips – and more carbon emissions.

The advent of fast delivery services is just one way in which online shopping risks losing any claim to be a more eco-friendly option than traditional trips to the shops.

Comparing the two types of shopping is tricky as their carbon footprints will vary depending on a multitude of things – whether a traditional shopper makes the trip by car or by public transport, whether an online order was delivered on the first attempt, whether the shopper did not return the item.

So when researchers at Heriot-Watt University in Edinburgh wrote an influential 2010 paper on the subject, they had to make a number of assumptions.

Their goal was to see how deliveries of small, non-food items from local depots to customers’ homes compared with personal shopping trips. They found that, on average, home delivery is likely to generate less CO2 per item than the typical shopping trip, but only if a shopper travelling by bus buys fewer than seven items per trip – and car users, fewer than 24.

If the research were repeated today, with express delivery growing in popularity, the findings might well be different. Either way, online shopping produces substantial emissions, and these could be reduced by opting for standard shipping whenever possible, even if the express option comes at no extra cost.

Another way to make online shopping greener would be to minimise returns, which require further shipping or trips to a store. Research by consumer experts Kantar earlier this year found that at least 42.5 per cent of Brits sometimes shop online with the expectation that they will be returning some of what they have ordered, and only 27.5 per cent never do that.

Shoppers are particularly likely to buy more items than they intend to keep when buying clothes, often ordering the same garment in more than one size to see which one fits. Retailers can help here by providing more detailed sizing guides on their websites, and many are already doing so.

A lower return rate would not only reduce the amount of packaging and emissions but also save retailers money, as processing returns takes up time.

Consumers, meanwhile, can vote with their wallets and buy only from those sites that provide clear sizing information. They can also contact those retailers that fall short to put pressure on them to improve.

Where online retailers clearly have a greater impact on the environment than bricks-and-mortar stores is in the amount of packaging they use. There are some signs of improvement on this front: 45 per cent use recyclable materials in their packaging, according to a study released earlier this month. But there is scope to do more.

Retailers could cut down on the amount of packaging – as, for example, Zara has done – and supply goods in bags or boxes that can be opened without being damaged. That way, they could be reused either by the retailer if the items are returned or by the buyer in their home. Again, as consumers, we can email or tweet at retailers about their packaging.

Such steps would benefit shoppers too. Returning unwanted goods takes time and effort – so much that, according to Kantar, 32 per cent of us don’t bother returning unwanted clothes bought online.

And one more thing for customers to think about: leaving Christmas shopping to the last minute isn’t just costly, but can result in some questionable purchases. In an email Argos sent round listing the most popular gifts they sold on 24 December 2018, hair stylers don’t sound too bad, toothbrushes are more mundane, but beard trimmers are downright risky.

So let’s all take our time next year. Avoid the last-minute panic if you can, spare a thought for the environment, and think about what express delivery really means. And merry Christmas everyone!