I'm not sure I understood your comment about the shape of the earth's orbit. The earth's orbit around the sun is an ellipse. But it's an ellipse that takes one

I'm not sure I understood your comment about the shape of the earth's orbit. The earth's orbit around the sun is an ellipse. But it's an ellipse that takes one year to traverse. The closest thing that gets us in terms of an "ice age" is winter. And, in fact, "winter" is what happens when you're closer to the sun, due to a change in the angle of incidence of sunlight (in the northern hemisphere). Are you referring to something else?