TOP 10 ICE AGES

 

Ice, ice, baby – and a shallow dip top ten on the spot for my Top 10 Ice Ages!

As I said in my entry for Ice Age in my Top 10 Ages, there have been a number of ice ages in the history of the planet such that I could compile a top ten of them, albeit I have to stretch it to get to ten since there are five or six major ice ages. (Not so much for special mentions, where I can get weirder and wilder with the subject, in what, aptly enough might be called my Ice Age iceberg).

So here they are (with all of them ranking as B-tier or high tier, with the exception of the top entry as A-tier or top tier)

 

 

A-TIER (TOP TIER)

 

(1) LATE CENOZOIC – QUARTERNARY (PLEISTOCENE)

 

No surprise here – the Ice Age, or the ice age everyone thinks of when they think of an ice age.

The most recent one – indeed, the one we’re stil in, albeit an intergalacial period of it. Hence in popular culture and usage the term Ice Age usually refers to the most recent glacial period within the larger ice age – the Pleistocene.

The one that began about 2.58 million years ago – the one with mammalian megafauna such as mammoths. And us – indeed, the Ice Age largely coincides with the (Upper) Stone Age (or Paleolithic), all the way back to our earliest hominin ancestors. We hunted the mammoth and all that.

 

B-TIER (HIGH TIER)

 

(2) LATE PALEOZOIC – KAROO

 

The next most recent Ice Age before our own – only 360 to 255 million years ago, preceding the dinosaurs (which first appeared about 243 million years ago). Also the most silly sounding name for an ice age with Karoo.

 

(3) EARLY PALEOZOIC – ANDEAN-SAHARAN

 

460 to 420 million years ago – life on land was just getting started.

 

(4) NEOPROTEROZOIC – STURTIAN, MARINOAN, GASKIERS & BAYKONURIAN

 

An ice age or series of ice ages from 720 to 635 million years ago (with encores 580 and 547 million years ago). Arguably this ice or these ice ages should outrank all others for a reason you’ll see in another entry on this top ten, but there wasn’t much life around to see it as it was just multicellular life getting started in the seas

 

(5) PALEOPROTEROZOIC – HURONIAN

 

Ice age – or at least three ice ages – approximately 2.5 to 2.2 billion years ago. Not much around to see it though with just cellular life

 

(6) MESOARCHEAN – PONGOLA

 

Oldest known ice age 2.9 to 2.78 billion years or so. Even less around to see it with microbian life.

 

(7) SNOWBALL EARTH

 

Okay, this is something of a cheat as Snowball Earth is a hypothesis that during one or more of Earth’s glacial periods, the Earth’s surface was “nearly entire frozen with no liquid oceanic or surface water exposed to the atmosphere”. I just like the name so couldn’t resist it for its own entry in my Top 10 Ice Ages.

There’s a less frozen version proposed as Slushball Earth “with a thin equatorial band of open (or seasonally open) water”.

Usually proposed for the Sturtian or Marinoan glacial periods in the Neoproterozoic Era, aptly enough within the period in that era called Cryogenian.

 

(8) LATE ANTIQUE LITTLE ICE AGE

 

A cooling period in the fifth and sixth centuries AD, hypothesized as a “volcanic winter” (more about that in special mentions) coinciding with three large volcanic eruptions and contributing to the decline of the Roman Empire – contrasting with the Roman Warm Period. So the decline and fall of the Roman Empire…was due to global cooling?

 

(9) LITTLE ICE AGE

 

A period of regional cooling, particulary in the North Atlantic, variously proposed from the 16th century (but also as early as 1300) to the 19th century (about 1850) with several causes proposed for it – contrasting with the Medieval Warm Period.

 

(10) NEXT GLACIAL PERIOD

 

We’re still in the Ice Age (the Quarternary Ice Age), just an intergalacial period – and some estimates are that we’re overdue for another glacial period, with human impact “now seen as possibly extending what would already be an unusually long warm period.”