There have been numerous ice ages followed by warming periods in earth’s history.
During the last ice age, Chicago was buried under a mile of ice.
Obviously things have thawed since then, but it was because Cro-Magnon man had coal fired power plants.
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Not only that, but I have it on good authority (Cueva de las Monedas) that Neanderthals owned huge, gas-guzzling automobiles.