Hmmmmm, let's see, where have I heard of this? Polar ice caps melting, causing an apparent retreat, then coalescing into ice and advancing again...hmmmmmmmmmmmmm, oh, yeah, the 4 Ice Ages. That's it. Apparently it's been going on for some time. Like a few million years, before man arrived on the scene too. It was in all the papers, did you miss it?