For the record:
I believe that the Quaternary Period, the glacial/interglacial cycle was the major
driver of this through the lifespan of Homo. But, it probably was going to happen
anyway only it would have taken orders of magnitude longer.
Plate tectonics didn't create "The Ice Age." It more or less predisposed us to
glaciations. It changed the currents. Most of the sun's energy falls along the
equator, the currents redistribute that energy across the globe. Change the
currents and you change that distribution. Cold spots form. And it took
HUNDREDS OF THOUSANDS of years but eventually the cold seeped down
even to deep ocean waters, and from there the glacial periods started to grow
The oceans are a battery, storing and releasing energy from the sun. They're
not warming, the deep waters are what's important here, the surface
temperatures fluctuate easily, which is why the fake science that is AGW
invented some non existing concept called "Ocean Memory" and started
babbling about how the ocean lost it's memory...
What they mean is that the data conclusively demonstrates no warming what
so ever. Well that contradicts the narrative, so now they pretend that the
ocean "Forgot" that it warmed... that's why it's not warmer... it simply "Forgot."
Anyway, all this really hit it's stride about a million years ago, so that's where
I'd look for everything being turbo charged...
But I honestly think you're right, that modern man basically began with your
erectus, and certainly before 1 million years ago, but "Climate Change"
would have been at it's biggest, as a factor, starting then.