From the file of “Things that would really be catastrophic”. Did a meteor have a role in a major shift in Earth’s Climate?
The start of the Quaternary period (2.588 million years ago, where the Pliocene became Pleistocene) coincides with evidence of a mega tsunami in the South Pacific.
The Eltanin Meteor fell into the South Pacific 2.5 million years ago setting off a (likely) tsunami that was hundreds of meters high and theoretically pushed mass material into the atmosphere which may have contributed to the cooling the globe had already started on. This meteor was hard to detect because it hit the ocean rather than the land. But researchers have pieced together evidence of the mass tsunami on continents around the pacific rim.