According to some reading I did years ago the earth wobbles on its axis. Could that be the cause?
Side note: Neither the rotational speed nor the orbital speed and distance are constant, as well. Some things to think about regarding “human-caused” global warming, IMHO.
No, the earth’s precession is a 25,000 year cycle. That means Polaris will no longer be the north star is a few thousand more years. But I think Mtn did a good explanation in post #8. It’s actually not that complicated.