Well that was the Ice age. I learned about it in history class in 1953 or so.
Well they brought it back in the 70’s!
We didn’t seem to be bothered by “cold” back then so it was resurrected as “hot” and put into grade school curriculum. And that worked!!!!
One of the essays I read discussed the effect of the Himalayas on our temperature. Cold air from Siberia comes down hits the mountains and bounces back to form our jet stream. Interesting.