They weren't. Not at all, gradual perhaps. I don't completely buy that either. Unlike the rapid effects today.

Rapid effects caused by humans populating rapidly.

Your gradual retreat, is only merited prior too geostorm, solar oburst, or impact, because it was a different climate. Then it froze. Today that result is humans populating. It was frozen. Today it isn't.

But you are completely discounting the fact right beside your assumed gradual retreat are all these millions of humans expediting it. Any natural effects increase with population.

They weren't. Not at all, gradual perhaps. I don't completely buy that either. Unlike the rapid effects today.

Rapid effects caused by humans populating rapidly.

Your gradual retreat, is only merited prior too geostorm, solar oburst, or impact, because it was a different climate. Then it froze. Today that result is humans populating. It was frozen. Today it isn't.

But you are completely discounting the fact right beside your assumed gradual retreat are all these millions of humans expediting it.