Carpets turning orange!

[batgirl_cdn]

I have some cream-coloured wool carpets, good quality but not super expensive (IKEA) and they are starting to turn orange-coloured - top and bottom! Is this due to the humidity? We haven't sprayed them with anything and we never put the carpets back down after washing the floor until the floor is dry.

Anyone with a similar experience, and any advice you can give about cleaning possibilities?

Thanks in advance.