Have you ever voluntarily put yourself between a rock and a hard place? That’s how comparing the environmental footprints of printed and electronic media feels. It could easily backfire. But let’s put away preconceptions and start looking at what we know.
Collectively, the paper versions of all the titles on an e-reader weigh more than a tablet and take up much more space—not only on a bookshelf, but also in delivery vehicles traveling from printing facilities to bookstores. And of course, the paper industry cuts down trees (removing carbon sinks in the process) and uses chemicals to enhance paper quality. Additional chemicals in binding glues and inks each have their own environmental footprint. Moreover, all the processes involved in getting a paper book into a reader’s hands require energy from different sources and have different emission profiles. Finally, at the end of its life, the book will most likely be recycled, affecting its overall environmental footprint by reducing the global need for virgin wood fibers.
E-readers don’t require trees, ink, or glue—nor do they take up as much space and weight as a traditional book. An e-reader represents not just one book but an entire bookshelf, so having more books on the e-reader reduces the environmental burden per book. On the other hand, e-readers consist of electronic components (such as the screen, lithium-ion battery, and CPU)—all of which require extraction and transformation of different resources (copper, silicon, and rare earth elements, among others). They use electricity to recharge, and the data centers and servers that host electronic books before they’re downloaded also consume resources and energy. What’s more, an e-reader has a shorter lifetime (around three years) than a paper book. And even though recycling electronic products continues to become easier, the practice is still not widespread and is much more problematic than recycling paper books.
If you read a limited number of books, the paper book will most likely limit your greenhouse gas emissions. But for heavy readers, e-books have a smaller carbon footprint.
So which one is better? As is so often the case, the answer is neither black nor white. A cursory review of the literature reveals that, although the topic has been well researched, studies vary in quality and rely on different assumptions and data to make comparisons. Variables include different sample size, different types of paper quality, different printing processes, different disposal methods (recycled or sent to a landfill), and whether books are single-use or read several times. In light of such variables, contradictory conclusions arise. Paper books can sometimes show the lowest carbon footprint (especially when comparing a lower number of books) or the highest carbon footprint (especially when comparing a high number of books).
To better grasp how the various assumptions affected the results, I built a life-cycle inventory model based on data from Naicker and Cohen (2016) because it was relatively recent and sufficiently detailed to fit my purpose. Naicker and Cohen compared reading 21 university textbooks of unspecified length and weight, either in a paper format or an electronic format on an iPad. I made several modifications to their model:
Accounting for the number of books: To account for a varying number of books, I adapted Naicker and Cohen life cycle inventory to provide indicator results for one university textbook instead of 21. For the iPad, I multiplied the life-cycle inventory of the iPad production, distribution, and transport by 21 (to have one iPad) and isolated the required electricity to edit, download, and read a single e-book. We also modified the iPad multifunctionality assumption, making it alternatively a 20-percent, 50-percent, 75-percent, or 100-percent e-reader instead of a static 64-percent e-reader.
Accounting for different paper quality and printing processes: The book-production process was mostly overhauled to account for different paper production (woodfree coated-average, wood containing light, woodfree uncoated–average, woodfree, uncoated 100 percent recycled content, woodfree coated at the integrated mill, woodfree coated at the non-integrated mill) and inking processes (laser printing black and white, laser printing color, printing offset) that were included in the ecoinvent v.3.4 life-cycle inventory database.
Accounting for different ends of life for paper books: Naicker and Cohen consider that the book will ultimately be landfilled. We accounted for the possibility that it will be recycled.
Accounting for spatial variability: I adapted the life-cycle inventory data of the manufacturing and the electricity-generation markets to account for three regions where the books would be manufactured and read: the United States, China, and Québec (Canada). These geographic entities represent the global range of values for electric-grid-mix carbon footprints, with Québec showing the lowest, China the highest, and the US close to the average.
I also relied on a different ecoinvent life-cycle inventory database (version 3.4 instead of version 3.01). Otherwise, I accepted the same assumptions and the same limitations that Naicker and Cohen specified.
The obtained greenhouse gas (GHG) emissions from this exercise are shown in Figure 1. Each additional paper book generates additional GHG emissions. On the contrary, with each downloaded e-book, the contribution to producing the e-reader is fixed, and the electricity required to download and read the e-book doesn’t contribute much to the carbon footprint. Furthermore, manufacturing or use locations don’t affect the conclusions as much as the number of textbooks (not shown on graph) compared to the number of books or paper and printing processes. Therefore, there’s a threshold at which books emit more GHG emissions than an e-reader and vice versa. Within this exercise, this threshold is assessed at somewhere between 13 and 30 (average 20) university textbooks—depending on a set of defined parameters and whether the iPad is used solely as an e-reader. If it is used for other purposes (such as navigating the Web or playing games), the GHG emissions from manufacturing the iPad are split among these different uses. If the iPad is used only 25 percent of the time for reading textbooks, this threshold is assessed at somewhere between four and eight (average five) university textbooks. Therefore, if you read a limited number of books, the paper book will most likely limit your GHG emissions. But for heavy readers, e-books are most likely to limit GHG emissions.
Pierre-Olivier Roy is a lead energy and senior consultant at The International Reference Centre for the Life Cycle of Products, Processes, and Services (CIRAIG), Montréal, Québec.