Back in the early days of worrying about the environment we looked at paper and pitied the poor trees that were sacrificed for it, hence the drive towards paper recycling and all that.
Now, however, with the urgent need to do something about CO2, there is an entirely new perspective: I can consider the 5000+ books in my household as a significant contribution to carbon sequestration. As long as our house doesn't go up in flames, there are tons of carbon safely locked away in our books, old magazines, papers, and all that.
People of the world, buy more books ! (Even if you don't read them, just keep them safe from fire and rot.)