Are e-readers really all that much better for the environment than books? The answer to that question is a resounding yes, at least according to Cleantech. The numbers break down thusly:

• A typical book has a 7.5 kilograms (~17 pounds) of carbon footprint.
• The iPad’s weighs in at 130 kilograms.
• The Kindle is estimated to come in at 168 kilograms.

Therefore, according to Slate’s Brian Palmer…

“…the iPad pays for its CO2 emissions about one-third of the way through your 18th book. You’d need to get halfway into your 23rd book on Kindle to get out of the environmental red.”

Considering the new Kindle’s gangbusters sales performance — Amazon still doesn’t release exact sales figures — it looks like the greening of the publishing industry is well underway. Catch the rest of the analysis over at the Washington Post.