I don’t even know where he got the ice age shit from

Some random blog or youtube video, most likely. It’s a standard go-to for climate change deniers - usually combined with some bullshit about Milankovitch cycles or solar cycles.

the eighty seven apocalypse movies about climate change causing a snap-back effect that flash freezes the planet, leading the best-dad to rescue his smart-boy large-child from urban-location, probably

I believe starting in the 70’s and continuing into the 80’s and 90’s, people were talking about a new ice age caused by widespread use of aerosols, and between the 40’s and the 70’s, there was some cooling happening, and some scientific papers suggested this would continue, though they were in the minority even at that time, as the effects of GHG’s were expected to overtake the cooling caused by aerosols by basically any reasonable model even back then… However, the “ice age” story was signal boosted by a lot of people in the MSM at the time. So, if you dad formed his opinion on the topic in the mid 70’s and just never really looked into it or was never really reading scientific papers, it’s easy that he just thought the one article he read on the topic from Time or Newsweek was still relevant…

Or it could just be the MAGA chuds at his work… and maybe they read it once in Time or Newsweek in the mid 70’s… Or they just made it up because they needed to combat the ACC science.