I buy everything online, especially grocery shopping, and I’m often told that this is bad for the environment. I wanted to check. Unfortunately, I couldn’t find anything on Wikipedia. The pandemic led to a significant increase in e-commerce, and today, 20% of US retail is online (vs. 30% in the UK), which makes this question even more relevant:
Consultancy firm Oliver Wyman did the most recent study on the subject. Analyzing three sectors—fashion, books, and consumer electronics—they concluded that shopping in physical retail stores in Europe resulted in 2.3 times more greenhouse gas emissions than online shopping. However, this study was commissioned by… Amazon! Another unpublished study by Amazon concluded that “online grocery deliveries generate 43% lower carbon emissions per item compared to shopping in stores, and smaller basket sizes generate even greater carbon savings.” Since then, Amazon’s CEO Jeff Bezos has repeated that online shopping “consistently generates less carbon than driving to a store.” Should we trust him?
I looked at other independent studies. In particular, a 2021 paper reviewed all the literature on the subject. If online purchases perfectly substitute offline ones and if you only consider “direct transport impacts” (first-order effects), then there can be considerable savings in fuel consumption. Transport distances are indeed naturally lower in home delivery rounds as compared to individual store visits:
The above picture isn’t entirely accurate as warehouses used for e-commerce are further away from consumers than shops. Also, consumers can use other modes of transport. On the other hand, 10% of shopping trips result in no immediate purchase. Taking all of that into account, one study concluded that a personal shopping trip by car emits 24x more CO2 than a single drop within a home delivery round while taking the bus lowers the difference to 7x.
However, the authors of the review insist there’s no perfect substitution as online shopping changes consumers’ behaviors. For instance, e-commerce facilitates fragmented shopping. There are more returns online, especially in clothing. As e-commerce grows, some brick-and-mortar shops close, forcing customers to rely on their cars more. So the authors conclude that “there is no particular type of shopping that has an absolute environmental advantage.”
Why such a difference with the results communicated by Amazon? Probably because the previous paper relied solely on transportation costs. Another study modeled the grocery supply chain. According to them, offline, customers buy large baskets infrequently, which leads to more food waste. They estimated that online shopping could lead to an 8-41% reduction in emissions. More congested cities with a lower physical store density have the biggest gains. The change in food waste in households is the key component in these results. 30% of food is wasted globally across the supply chain, contributing 8% of global greenhouse gas emissions. If food waste were a country, it would be the biggest emitter of CO2 after the US and China.
Many other factors give online shopping an advantage over physical retail. For instance, the fleet of e-commerce companies is greener than the average car: Amazon recently bought 100,000 electric vehicles and aims to be carbon neutral by 2040.
In physical retail, overstocking is also standard—consumers are more likely to buy from abundant-looking displays—leading to more waste. There’s better inventory management in the warehouses of e-commerce retailers.
And a traditional supermarket is energy-intensive: it is maintained at a comfortable temperature for shoppers while keeping food items refrigerated and frozen. On the contrary, warehouses operate at lower temperatures, and they don’t have the issue of constantly opening and closing entry doors.
Based on these studies, I think that Jeff Bezos is right when he says that: “shopping online is already inherently more carbon-efficient than going to the store.”
That being said, what you buy has way more impact than how and where you buy it. One study on meal kits found that food production was responsible for 65% of a meal’s carbon footprint. Whereas “transportation and logistics associated with the last mile are a pretty small overall contribution to the total environmental impact of food.”
So don’t listen to the naysayers: online shopping is good for the environment! And send them this article next time they criticize you for buying online 😉