None. Also scarcely ever mentioned is the earth’s distance from the sun in the elliptical orbit.
You'd probably be interested in the Milankovitch cycles. Basically there are multiple cycles the earth does. One has to do with the wobble on the rotational axis. Even the earth's orbit (which you point out is elliptical) has cyclical variations on the shape of the orbit. IMHO, these Milankovitch cycles are the main cause of the various warming and cooling cycles.