Is it more sustainable to have an item delivered to your home or to drive to pick it up at the store? What if the store is near your office?
New research from Spain suggests that it’s how orders are fulfilled—not just how many orders—that play a key role in carbon emission rates. A study published in the international, peer-reviewed journal Sustainability stipulates that omnichannel fashion retail models produce lower last-mile emissions than online-only pure players, largely due to customer travel behavior and store locations.
The research, conducted across 11 Spanish cities and based on 3,106 in-store customer surveys, compares Spanish fashion retailer Tendam’s click-and-collect and in-store return model with benchmark data from online-only fashion retailers. Spain was selected because of its concentration of medium-sized cities, omnichannel maturity and policy toward low-emission urban zones.
According to the study, the average carbon footprint per omnichannel transaction is approximately 400 grams of CO₂-equivalent. In contrast, pure play fashion e-commerce generates between 1,500 and 3,000 grams of CO₂-equivalent per order, assuming one apparel item per package, and based on simulation models from prior research conducted in Monte Carlo.
This represents a carbon reduction of roughly 73% to 87% per purchase when consumers pick up an item in-store rather than receive it via home delivery. E-commerce is the fastest-growing sales channel, which points to a magnified carbon emissions impact over time. According to the World Economic Forum, business-to-consumer (B2C) e-commerce grew 20% to 25% annually worldwide for more than a decade. As such, deliveries to meet such demand will grow road transport greenhouse gas (GHG) emissions in the world’s 100 largest cities by 30% by 2030, said the report, unless corrective measures are implemented.
While earlier research has produced conflicting conclusions, notes the report, this study suggests that store proximity, transport mode and return handling may outweigh delivery efficiency gains claimed by pure e-commerce players. The study focuses only on last-mile distribution—not production or end-of-life impacts—and adds new evidence to an ongoing debate about the environmental cost of e-commerce. For brands, this reinforces the strategic value of dense, well-located store networks; click-and-collect and in-store returns; and integration with walkable urban infrastructure.
Two main factors are driving the omnichannel vs online carbon emissions gap: customer movement patterns and high return rates in fashion e-commerce. Sustainability attitudes can also impact channel choice, with younger consumers in particular leaning toward experiences that align with their environmental values.
The omnichannel emissions advantage was most pronounced in large cities (over 1 million inhabitants) and in street-level stores, where walking rates were the highest. In such urban contexts, many customers either walk to the store or combine shopping with other activities (commuting, running errands) in a behavior known as “trip chaining.” Because the emissions of such activities were sunk costs, the additional carbon footprint of collecting or returning an order was minimal. In short, walking isn’t just healthy, it’s environmentally friendly, and urban design with dense store networks in walkable areas can play an important role in retail sustainability.
Returns Run Up Biggest Carbon Risk
Returns are the dark side of e-commerce’s high convenience. Fashion e-commerce has some of the highest return rates in retail, exacerbated by fit issues and size bracketing, and the study highlights the environmental cost.
Beyond the carbon impact of returns, previous research cited by the authors showed that between 22% and 46% of clothing and footwear returns are never reused.
Dealing with these unused returns creates between 2 and 16 times more GHGs than the emissions from returns shipping, packaging and handling alone. Pure play online returns are frequently shipped long distances where they are either destroyed or inefficiently recycled. In contrast, in-store returns—when managed effectively—allow faster redistribution and higher reuse rates, significantly reducing emissions.
As regulators push for urban decarbonization and consumers demand greater transparency around sustainability claims, the research suggests that physical retail—far from being a liability—can be a critical lever for reducing fashion’s last-mile carbon footprint. Even so, findings highlight the need to assess a product’s full product life cycle and logistics processes when comparing retail models, not just the last mile.
