The Millions has a great write-up of the real impact of e-readers. Despite the notion that if you read enough books on them, they'll have a lighter footprint than printed books, the reality is something less appealing altogether.
"Necessarily, the increased consumption of print and digital books has led to an ever-increasing demand for the materials required to create, transport, and store them. In the case of eBooks, though, vast amounts of materials are also necessary for the eReaders themselves, and this is something typically overlooked by proponents of digitization: the material costs are either ignored, or, more misleadingly, they’re classified as the byproduct of the tech industry instead of the book industry... In other words: the carbon footprint of the digital book industry is mostly growing in addition to, not to the detriment of, the growing carbon footprint of the print book industry."
The analysis Nick Moran performs to determine just how bad the carbon footprint of the e-reader industry is provides us with some interesting numbers.
"That eReader, then, accounts for an initial carbon footprint 200-250% greater than your typical household library, and it increases every time you get a new eReader for Christmas, or every time the latest Apple Keynote lights a fire in your wallet. Also, these figures simply calculate the impact one person’s consumption has on the environment. If you live in a household with multiple eReaders — say, one for your husband and one for your daughter, too — your family’s carbon emissions are more than 600-750% higher per year than they would be if you invested in a bunch of bookshelves or, better yet, a library card."
Unless you are both an incredibly avid reader as well as someone who cares for their gadgets and does not replace or upgrade to new models, e-readers just simply don't live up to the lighter footprint they promise. Instead, we should stick with our library cards.
If you want a well-written reality check about reading, the footprint of the book industry, and the unfortunate truth about e-readers, you really want to read this article. It's worth the energy your laptop/smart phone/tablet uses while you're reading. I promise.