"By my estimation, I read about 20 books last year. I was given or purchased 7 new books, and the rest I checked out from the library, bought from a used bookstore, or were leant to me by friends. At this rate, it would take about three years of Kindle use for me to realize any net greenhouse gas benefit. Since I read a lot more than most people I know, I expect it would take the average person even longer to overcome the climate costs of the new device, if they realize any environmental benefit at all. For example, upgrading to a newer ebook reader model before reaching the "break even" emissions point of 22.5 ebooks would appear as a net increase in greenhouse gas emissions when compared with the carbon footprint of physical books."