How long does it take a CD to decompose?

Answer 1

CDs are generally made of polycarbonate plastics, which effectively do not decompose. However, the reflective portion of the disc can degrade to the point where the disc is unreadable in a relatively short amount of time; for recordable discs in a harsh environment, this could easily be as little as a few years; pressed discs using a thin layer of gold could potentially last centuries.

Answer 2

5 million years