5th question,… why does the “climate change” or in other words why do ice ages occur?
I’d phrase this differently
Why does Earth’s Temp go up and down and up and down?
Earth’s Temp is directly proportional to the Am’t of Solar Irradiance reaching Earth’s Surface.
Particulates/Black Carbon/Soot and SO2 acid - from e.g,. Volcanic Emissions block Solar Irradiance.
Periods of Exceptional COLD have always been detrimental to LIFE in varying degrees…
Impact upon Flora / food supply along with extreme cold and even loss of rainfall during extremes (b/c much water is locked up as ICE) likewise impact upon Fauna… contribute to Drought, Mass Migrations…
During the last glaciation in the history of modern man… c 12,000 give and take YBP, for starters, In the E.G. Northern Hemisphere, ALL of Canada and portions of The USA - were completely covered in v.very thick ICE…
Globally, Sea Levels were down an astounding 400 feet!
Generally
w/the exception of some regional areas of relatively shortish periods of Time,
periods of WARMTH are associated with Lush & GREEN.