[lazide]

Not proposing it ever actually happened, but one hypothesis [https://en.m.wikipedia.org/wiki/Snowball_Earth].

Personally, I’m of the ‘shits whack yo’ school of geohistorical projections. So got me. I’m still pondering what weird confluence of events could cause Salt Domes combined with massive oil and natural gas deposits like in the Gulf of Mexico.

Chicxulub?

Something else?

One thing is for sure, the more you understand and analyze the geological record, the more the doomsday preppers seem like insane optimists!

[medstrom]

That's still not really a hypothesis that connects to TFA as we're still basically proposing "well, the water just flowed down from higher up!" Put it this way, Snowball Earth is not itself a hypothesis for where'd the snow come from to make the snowball.

Also doomsday preppers live on the scale of a human lifetime -- you do agree that geological events don't really factor in?

[lazide]

Original water came from comets, and the protoplantary nebula. Notably, as ‘high up’ as it’s possible to get eh? And frozen.

And doomsday preppers are a personality type visible across all civilizations in some form - due to humanities evolved genetic heritage.

Just like every other type.