Whats Happening To My Stamps In The Stockbook, Help

So a slipcase, and improved ventilation won't do any difference in terms of preventing (or lessen the risk) of toning and foxing due to environmental causes?

I found another very good example (even worse than my stamps) on an auction site. You can clearly see how many of the stamps are bending out in a U-shape or whatever you want to call it. While some lay flat. Im convinced that it has to do with the gum in combination with maybe temperature as many of you already stated. And as I said before when they bend out like this they become stiff and crispy-like.

Another theory is that the hinge is causing this or at least making it worse.

I forgot to ask, why is it that some stamps watermark becomes more visible, and some stamps colors goes through to the back???? Almost like the gum is dissolving, or is thinning out making it more translucent.

Ok so I have bought the hygrometer now and have it turned on. It shows exactly 30-32% humidty where my stamps are stored, temperature 21 Celcius. So this is the reason that the stamps feel "stiffer" and slightly bend/"curly"?

I put a bowl of water next to the radiator and a wet towel hanging on the radiator (which is off), and the humidity increased to 36%. It's placed about 2 meters from the stamp albums.

Is this the right approach?!

(It's wintertime here in Sweden I might add, and -2 degrees Celcius outside.)