Geology Liveblog: Snowball Earth, or, How The Earth Got So Hot It Ended Up Very Cold

As much as the more rock-y geology is fun, I think it's time for a quick foray into paleoclimatology!

As a caveat: whether the Earth ever was a snowball (ie completely covered in ice), a slushball (mostly covered in ice), or was never either of those things is very controversial. Scientists are still duking it out. I am not an expert on these matters; take what I say with a grain of salt.

If you look at sedimentary rocks from about 717 million years ago, you'll notice something odd. Mostly that there aren't any, and there are gaps in the sediments where they should be. And when you do find some, they're distinctly glacial--even if they're from a place that should have been in the equator at the time, and not at the top of a mountain.

And even weirder, if you looked at the carbon isotope ratios of that time look like a bunch of methane, a greenhouse gas, got dumped into the atmosphere. ...and made things colder. Somehow.

Huh?

( Isotopes: A Paleoclimatologists Best Friends )

( Feedback Loops: The Good, the Bad, and The Positive )

( It's Like An Integer Overflow But For the Whole Earth )