Yes, and glaciers several miles thick covered the Midwest. Then ensuing global warming (NOT MAN MADE!) melted all that ice forming the largest body of fresh water on earth, we call the Great Lakes.
Climate change as you said, has been going on since earth was born. What many forget is the MAN MADE aspect. Man has such small impact on nature, the astronauts circling earth just 100 miles above, can not see a damn thing man has constructed. Only the Great Wall of China is seen as a barely discernible squiggly line.
Didn’t know those facts. Wow. Really? wow.