The second clue is that Northern Hemisphere glaciation intensified between 3.1 and 2.5 million years ago, thanks to all the moisture delivered to the far
north via evaporation from a more vigorous Gulf Stream.
2] Sahara expands > more dry heat > increases
evaporation in Mediterranean that should be for replenishing the ice — siphons more water from Mexican gulf — from Arctic ocean —
via Bering straights warm / salty water from
north Pacific.