I believe when that meteor hit Earth around 12,000 years ago, it created a massive dust cloud in the air. It's as if you're shooting a bullet into a big ball of sand. The dust cloud stayed, blocked off sunlight. The lack of sunlight cooled down the Earth, heavily, for a long time. This is what Randy Carlson's research is also based on. He spoke about studying the effect of the glaciers from this period on the geography of North America, which is very close to where the impact happened, which apparently happened in the Gulf of Mexico. He's done multiple podcasts with Joe Rogan talking about how they've tracked the movement of the glaciers in North America, et cetera.