Orbital forcing is a farce. The slow acting nature of orbital forcing can't be responsible for abrupt cooling and abrupt warming. Which is why no real science has been done on it. It's only basis is a poor correlation for cooling. The oceans on the other hand have had lots of science to show how changing ocean currents were responsible for glaciation and deglaciation.Both right and wrong. The southern oceans, because of their greater extent, absorb more heat at the beginning of the warmer periods at the start of the interglacials controlled by the Milankovitch Cycles. The relationship between the oceans and land masses are not simple. And the rise of the Himalayan Mountains, like the rise of the Appalachians in the Ordovician Period, reduced the amount of CO2 in the air by chemical weathering. At a slow enough rate that animals and plants had to time to evolve and migrate to adjust to changing conditions. That is not the case with AGW. Not only that, but we have effectively block most migration routes. So we are at the beginning of the sixth great extinction event.
Yes, plate tectonics played a huge part in setting the stage for bipolar glaciation. Besides the Himalayan and the Panama isthmus, the thermal isolation of the polar regions played a huge role. All of which are reasons is why the northern hemisphere is subject to glacial cycles in the first place.
But if you disagree feel free to show how orbital forcing caused D-O events.


