Earth wobble

[Al Cornett]

A recent History Channel program "How the Earth Was Made" stated: "Next wobble in the earth's axis is set for 15,000 years from now." They were relating this to the changes in the Sahara desert about every 7,000 to 8,000 years, from vegatative environment to desert, and the tilt of the earth caused these changes. Sounds like they are relating it to the Precessional cycle. I cannot recall or find out why this is so. I thought this phenomenon was dependent upon several things - earth's orbit, comets or asteroids hitting earth, close encounters with a body such as planet x, etc. I think they should have said a CHANGE in earth's wobble" or, "a beginning of a new precessional cycle." Anyone know a scientific reason justifying this statement?

Al C.