[harshreality]

Break-even according to one study is 22.5 books over the lifetime of an ereader.[1]

I found a separate source estimating that a paper book (typical) has a CO2 offset of about 2.6 kg CO2. I think that's just production costs, but just considering those, it takes only on the order of 50 books over the lifetime of a device to break even. Once you factor in CO2 output from the supply chain and more dwelling space to accommodate more bookshelves, break-even is probably in the neighborhood of the study's figure.

There are other reasons that's probably not a fair comparison. Ereaders seem to increase people's book consumption. Reading means not doing things like driving around for entertainment, so buying an ereader even to read books you already have might be a net positive on CO2 output.

[1] https://www.cnet.com/culture/study-paints-kindle-e-reader-a-...