With respect to the Earth's axial tilt, I was watching a show on TV about how humans migrated out of Africa. It showed how as the axial tilt changes, the equatorial desert belt belt moves further north or south. So in several thousand years, the Sahara Desert will be known as the Sahara Jungle.
Stuart, that sounds like an interesting doco, I would have liked to have seen that.
If you remember the title would you mind posting it here? Maybe I'll be able to find it on YouTube