claim: The geologic record provides us with abundant evidence for such perpetual natural climate variability, from icecaps reaching almost to the equator to none at all, even at the poles.
evidence: About 60.5 mya at the Danian/Selandian boundary, there is evidence of anoxia spreading out into coastal waters, and a drop in sea levels which is most likely explained as an increase in temperature and evaporation, as there was no ice at the poles to lock up water.
category: Paleocene