Bits o’ carbon: digital downloads are greener than CDs

Written by adam


This is hardly a shocking result, but it’s kind of fun nonetheless: a life cycle analysis reveals that downloading music digitally creates less than one sixth the carbon emissions of buying it from a retail store (pdf).

The study compares six scenarios:

1. Music purchased from a traditional retail store
2. Music purchased from an online retailer and delivered by truck
3. Music purchased from an online retailer and delivered by plane
4. Digital music purchase (e.g., via iTunes or
5. Digital music purchase burned to CD
6. Digital music purchase burned to CD and then stored in a plastic jewel case

As the graph above shows, the jewel case and the CD do add meaningfully to the carbon impact of the music download, but all three digital versions of the album are environmentally friendlier than the physical versions, despite the electricity consumed by the internet delivery infrastructure and the shopper’s computer.

Note that well over half of the emissions of the album purchased from a physical store come from the car ride to the store. This portion of the footprint will vary dramatically based on the purchaser’s proximity to the store and choice of transportation. In the best case — a trip on foot or by bicycle — buying a CD in a physical store has about the same impact as downloading it, burning it to CD, and storing it in a jewel case.

In semi-related news, several universities are experimenting with using the Amazon Kindle electronic reader to deliver electronic textbooks to students — and they’re claiming sustainability as a primary motivation. This notion rubs some people the wrong way. Books are low-tech, durable, and ostensibly derived from renewable resources. Electronic readers are cheap-looking plastic devices that need to be plugged into an outlet and presumably will end up in a landfill when newer models come out.

It’s not clear to me, though, which way the scales tip. Book are not, of course, completely benign. Energy goes into their manufacture, transport, and disposal. Beyond that — and here I speak as a Kindle owner — electronic readers do result in at least some energy savings by supplanting computer use. I suspect that physical books retain an edge over their digital cousins, possibly a substantial one. But I’d be curious to see some actual numbers.

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  1. JZ

    Granted, I am a music snob, but the quality of the downloads and subsequent home-archiving is simply less. In fact, all audiophiles know that for range and color of sound rendering, vinyl is the absolute best. Plus, why is nobody bemoaning the loss of album art? Liner notes and artwork are just as vital to the scholarly collection and enjoyment of recorded music as it is toward it’s marketing and sales.
    I would suggest that this is not a true apples-to-apples evaluation since the qualities of the products are dissimilar.

  2. darooda

    Maybe I’m too old fashioned, but I prefer to stick with books. It’s a hobby that for me is relaxing in it’s simplicity. Unplugging for a while and enjoying a book, is a behavior I would struggle to break even if there were significant environmental benefits. Ultimately, either way it’s probably in the noise.
    Now music on the other hand, I’m fine with the low res digital versions. I know it’s not as good, but since I mostly listen to music at the gym or in the car, most of those subtle differences are lost on me.

  3. Adam Stein

    Incidentally, the study authors did acknowledge that digital music downloads and physical albums aren’t perfectly equivalent items, because of sound fidelity, album art, etc. But of course equivalence is largely in the mind of the consumer, and most people seem pretty happy to accept the tradeoffs. Personally, I haven’t bought a CD in years, except occasionally at shows — and I then proceed immediately to rip them to mp3…

  4. Jake

    The retail amount looks like it doesn’t includ shipping the product to the store, which should add an additional amount.
    …to JZ’s point – I think the people out there optimizing for audio quality are a minority. At this point most people are happy to trade audio quality for being able to listen anywhere. So, I’d argue that for most people its still a valid comparison.

  5. Adam Stein

    The study does claim to include that emissions source, but it doesn’t show up in the graph (note that the e-tail options also need to account for emissions from shipping to the e-tail warehouse). I think what’s going on is that the emissions from the “Freight, Road” category is so low that they aren’t visible in the graph.
    This is another demonstration of why “localism” is a bit overblown as a solution to climate change. Shipping emissions generally aren’t a huge portion of the emissions embodied in a product.

  6. Pablo

    Great information! This new study supports my findings in my article on the subject from May 2007: Ask Pablo: Online Shopping

  7. James

    I’m with JZ on this one. As a musician, I have a hard time shelling out cash for inferior mp3s, and usually opt to purchase the album (used) instead.
    However, there is an emerging solution: Daniel Lanois, for instance, has begun offering downloads of his albums as .wav files, which are lossless, for the same cost as mp3s with downloadable album art included. That becomes a no-brainer for me.

  8. Lorne Craig

    Love the digital format of music, despite its quality, and I think there may be more opportunity for ‘album art’ in a digital format as well.
    Regarding the Kindle vs. Books debate, does anyone else ever get the feeling that educational information delivered solely in digital form might be a bit too easily modified according to the political whims of the day? A book, once printed, is also a record of historical fact. Digital information, less so.

  9. Brian

    This is the first reader I have owned so I can’t compare to others but I can say that it is truly an ‘amazing’ little device. My son is a child with medical problems so I spend a lot of time in doctor’s offices and at therapy with him. My arms are usually loaded down with the things he needs/requires on these visits. He is in a wheelchair so that’s one more thing I have to bring along. With Kindle 2, I have all these book at my fingertips and on top of that, I can use text to speech to have children’s books entertain my son during these long waits. It is simply amazing.