One thing which isn’t often discussed is the annual cycle in incoming solar radiation. The typically quoted values of 1360 or 1365 W/m^2 represent the amount received at a hypothetical Earth which is always 1 Astronomical Unit away from the Sun. In reality the Earth’s orbit is slightly elliptical so is receiving different amounts at different times of the year.
The SORCE data suggests that solar energy received at Earth distance varies from about 1400 W/m^2 in the SH summer to about 1310 W/m^2 in the NH summer. The trade off for the SH is that their Summer period is shorter at present orbital and axial configurations.
I think it was Chief Hydrologist who posted a graph showing an ENSO reconstruction over the past 10000 years. The changes in ENSO appeared to correlate quite nicely with the changes that would have happened to this annual cycle over the period. That is, about 10,000 years ago the cycle would have been flipped such that the NH was receiving the maximum solar dose in its summer. I don’t know if there has been much published research on this.