Not All E-commerce Emits Equally: Systematic Quantitative Review of Online and Store Purchases' Carbon Footprint

Although it has been studied extensively throughout the past 20 years, the environmental impact of e-commerce can still be considered a controversial subject. Particularly for those wondering whether online shopping constitutes a more environmentally friendly alternative to traditional store-based shopping, evidence can be found that quantitatively supports affirmative as well as opposing claims. Findings differ widely because the contexts and assumptions of the studies from which they are drawn differ widely as well. To advance our understanding of this question and inform actions that can actually reduce the environmental impact of shopping, we carried out a systematic quantitative review of environmental impact assessments that compares the carbon footprint of online and store purchases. Based on over twenty scientific studies, we compiled a dataset of 244 purchases, their estimated carbon footprint and information on the contextual, distribution, behavioral, and geographical conditions on which the calculations are based. We conclude from the reviewed studies that online purchases generally generate a lower carbon footprint than store purchases, but only in the case of car-dependent lifestyles, and possibly only because the studies largely overlook transformations in consumer behavior and in the consumption landscape.