The planet transitioned from a greenhouse planet to an icehouse planet ~3 million years ago. In large part due to the polar regions being thermally isolated from warmer marine currents. The planet is uniquely configured for bipolar glaciation and colder temperatures. Climate fluctuations increased as the planet transitioned to bipolar glaciation. In large part because of the land distribution in the northern hemisphere around the arctic circle.Sick liar. Too obvious. Remind us of your "answer"
LOL!!!
Now please go away.