Information technology has a carbon footprint, that’s beyond doubt. Now, writing in a special issue of the Journal of Industrial Ecology, Christopher Weber, Jonathan Koomey and Scott Matthews in the US in work supported by grants from Microsoft Corporation and Intel Corporation have calculated that purchasing music digitally reduces the energy and carbon dioxide emissions associated with delivering music to customers by between 40% and 80% from the best-case physical CD delivery, depending on whether a customer then burns the files to CD (it’s five times better if they don’t). They point out that digital media services, such as subscription and streaming systems, like Spotify, last.fm and Pandora have higher energy usage than direct downloads, such as iTunes, Zune, amazon mp3 or any of myriad file sharing tools.
The team concedes that their calculations are very sensitive to both behavioural assumptions of how customers use digital music and several important parameters in the logistics chain of retail and e-tail delivery, such as customer transport to the store, CD packaging method, and final delivery to the customer’s home for e-tail.
“In particular,” they say, “online music’s superiority depends on the assumption that customers drive automobiles to the retail store.” Therein lies one of the biggest issues surrounding any carbon footprint calculations: the fact that it is relatively easy to overlook or overegg a specific factor depending on the stance one wishes to take.
Weber, C., Koomey, J., & Matthews, H. (2010). The Energy and Climate Change Implications of Different Music Delivery Methods Journal of Industrial Ecology, 14 (5), 754-769 DOI: 10.1111/j.1530-9290.2010.00269.x
Weber is at the Science and Technology Policy Institute in Washington, D.C. and Carnegie Mellon University. Koomey was visiting professor at Yale and is now at Lawrence Berkeley National Laboratory. Matthews is at Carnegie Mellon.