A recent study conducted by Carnegie Mellon University, Dept of Civil and Environmental Engineering, Lawrence Berkeley National Laboratory and Stanford University found that buying music online can decrease carbon emissions and energy usage by 40% to 80%.

The report analyzes the environmental benefits of using services such as iTunes and Amazon to buy music, versus traveling to a brick and mortar shop to buy a physical album. What determines 40% or 80%? It depends on a few factors, among them packaging, shopping methods and delivery methods.

The study used the following music-buying scenarios in their research:

1) Album published on CD and delivered via traditional retail methods
2) Album published on CD and delivered by light-duty truck through an online e-tail
provider
3) Album published on CD and delivered by express air through an online e-tail
provider
4) Album downloaded as mp3/mp4 files from an online music service and used
digitally
5) Album downloaded as mp3/mp4 files from an online music service and burned to
CD-R for digital and CD use (no CD packaging)
6) Album downloaded as mp3/mp4 files from an online music service and burned to
CD-R for digital and CD use, stored in individual CD packaging, i.e., slimline jewel cases

The only situation in which buying from a store would be superior than downloading online would depend on a) the size of the downloaded album and b) how the customer is getting to the store. It is possible that the energy spent on turning your computer on, connecting to the internet and downloading the file would be larger than if the customer just walked to the store to buy it.

But all in all, online music downloading is far more eco-friendly. The researchers concluded, "Based on our assumptions, online delivery is clearly superior from an energy and CO2 perspective when compared to traditional CD distribution."

These stats aren't exactly shocking, packaging and fuel for delivery trucks are an obvious waste of carbon emissions, but it's nice to see evidence in numbers nonetheless.