[Rockhounds] Scientists match Earth's ice age cycles with orbital shifts

[Dora Smith]

I just sent three replies to the person who wrote the posts instead of 
the list.

This (changes in earth's orbit) isn't at all a new idea, but, I believe 
the correspondence is far from exact and other things play a role.  
Before the western hemisphere took its current configuration there 
weren't ice ages!

There have been extremely long periods of earth's history lasting a 
billion years or more where the entire planet was outright hot.


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How did this eruption compare with the Tobo supervolcano around the same 
time, that is thought to have driven the human race to the verge of 
extinction?  It buried India under many yards of ash, and caused a 
definite volcanic winter.  It is thought that only humans living in 
certain parts of Africa at that time could have survived.  Humans lived 
in Asia, but they didn't survive.

The Tobo eruption is supposed to have been bigger than those of 
Yellowstone, that would destroy civilization as we know it if it erupted 
the same way today.   Was Los Chocoyos puny by comparison?

I'm actually feeling a little skeptical, because every single time 
scientists find a world changing eruption that changed the course of 
humanity or civilization, someone else says oh no, this other volcano in 
South America did it, for the sake of argument, just to deny reality.

-----------------------------------

Wait - what caused that ice age, the last one before the most recent 
around 45,000 years ago - changes in Earth's orbit around the sun, or, 
volcanic eruptions?  LOL!

I have been of the opinion that a volcanic winter might help push the 
planet into an ice age that other forces were already inclining it toward.

---------------------------------------------

When I looked into it, I found that this Nature article thinks both 
eruptions caused an ice age.  I still don't think they caused it all by 
themselves, especially not if they occurred 10,00 years apart.  Toba is 
not exactly dated.  Over the long years since it was blamed for 
humanity's population bottleneck, I have seen 65,000 and 75,000.

https://www.nature.com/articles/s43247-021-00293-6

They were both huge eruptions.

Yours,

Dora


On 3/1/25 1:32 PM, Kreigh Tomaszewski wrote:
> Beginning around 2.5 million years ago, Earth entered an era marked by
> successive ice ages and interglacial periods, emerging from the last
> glaciation around 11,700 years ago. A new analysis suggests the onset of
> the next ice age could be expected in 10,000 years' time.
>
> The findings are published
> <https://www.science.org/doi/10.1126/science.adp3491> in the journal
> *Science*.
>
> An international team, including researchers from UC Santa Barbara, made
> their prediction based on a new interpretation of the small changes in
> Earth's orbit of the sun, which lead to massive shifts in the planet's
> climate over periods of thousands of years. The study tracks the natural
> cycles of the planet's climate over a period of a million years. Their
> findings offer new insights into Earth's dynamic climate system and
> represent a step-change in understanding the planet's glacial cycles.
>
> The team examined a million-year record of climate change, which documents
> changes in the size of land-based ice sheets across the Northern hemisphere
> together with the temperature of the deep ocean. They were able to match
> these changes with small cyclical variations in the shape of Earth's orbit
> of the sun, its wobble, and the angle at which its axis is tilted.
>
> https://phys.org/news/2025-02-scientists-earth-ice-age-orbital.html
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