This has never happened before except when I left books in the car and it rained. The paper absorbed the moisture from the air and the pages get a distinct wavy shape. I was able to mostly fix them by standing them up and fanning out the pages. I blew air over them with an electric fan. Now I just noticed that almost all of my books in my apartment have these signs of moisture. I knew that I did not have ideal climate controlled conditions but this has never happened in ten years. In fact, I had the opposite problem with the air too dry in the winter from radiator heat. The covers would warp outwards. I addressed that with a tabletop humidifier and also by putting pots of water on the radiators. We had snow on the ground until a week ago and then suddenly it got warm and humid maybe two days ago. I think the sudden change has been a culprit. We seem to have skipped spring and went right to sweltering jungle conditions.
Now, I can start to dry them out as before but there is one problem. I have about 3000 books. Would it help if I turned on the air conditioning to dry out the air? Does this go away in a few days as some sort of equilibrium is established? I noticed the same thing today at the school where I work. My books and those of my colleagues had the same condition in out offices. It has been very warm and humid the past two days. I talked to the librarian and she seemed oblivious and was not too concerned. I found the picture below online to show what this can look like.
