The End of the Early Bronze Age

November 8, 2024 1:31 PM

Did a mega drought topple empires 4,200 years ago? is an article by Michael Marshall in Nature [archive link] about the debate around the 4.2-Kiloyear Event, which was possibly a major shift in global climate patterns that started around 2200 BCE. The effects were especially stark in the Fertile Crescent, where social complexity decreased markedly, empires fell, and cities were abandoned, as recounted in the video essay The First Bronze Age Collapse and the Intermediate Bronze Age. If you want more granular detail, best known archaeological site for this period has a good website with lots of information, The Tell Leilan Project.
posted by Kattullus (16 comments total)

That's roughly the time of Abraham's migration from southern Iraq to Canaan.
posted by ocschwar at 2:08 PM on November 8 [2 favorites]

It's pretty easy for those of us living in a post-Haber-Bosch world where the problem is arguably an excess of easy calories, to grasp just how tenuous societies in the past could be. Widespread and persistent drought like the one described in the article, were literal apocalyptic events. It seems obvious, but it really is shocking how often the end of kingdoms and empires are tied to a few years of bad harvests.
posted by Panjandrum at 3:56 PM on November 8 [11 favorites]

Europe itself was on the verge of demonstrating your point when Haber and Bosch invented the process.
posted by ocschwar at 4:19 PM on November 8 [4 favorites]

holy smokes, I recall drought being a factor in the collapse of the Old kingdom in Egypt.

I did not know it reached as far as the Indus valley and the lower Yangtze River.

"Modelling evidence suggests that the 4.2 ka event was the result of a significant weakening of the Atlantic meridional overturning circulation (AMOC), disrupting global ocean currents and generating precipitation and temperature changes in various regions"

Hmm
ah-ha
posted by clavdivs at 4:40 PM on November 8 [4 favorites]

Patrick Wyman did some fantastic Tides of History podcasts on this period which covered the drought theory.

See this one and the rest of Season 4: https://wondery.com/shows/tides-of-history/episode/5629-what-was-the-bronze-age-collapse/

In fact try this search result for a whole bunch: https://wondery.com/search/?epPage=12&term=bronze+age+collapse&mode=all
posted by i_am_joe's_spleen at 4:58 PM on November 8 [2 favorites]

Second for the Wyman podcast, he’s good at the details and has insightful interviews with relevant academics.
posted by billsaysthis at 7:47 PM on November 8 [1 favorite]

In year old related news:

The Gulf Stream system could collapse as soon as 2025, a new study suggests. The shutting down of the vital ocean currents, called the Atlantic Meridional Overturning Circulation (Amoc) by scientists, would bring catastrophic climate impacts.

Amoc was already known to be at its weakest in 1,600 years owing to global heating and researchers spotted warning signs of a tipping point in 2021.

The new analysis estimates a timescale for the collapse of between 2025 and 2095, with a central estimate of 2050, if global carbon emissions are not reduced. Evidence from past collapses indicates changes of temperature of 10C in a few decades, although these occurred during ice ages.

Gulf Stream could collapse as early as 2025, study suggests

I am y2karl and I try to post something positive every day but you know, sometimes stuff comes up...
posted by y2karl at 9:39 PM on November 8 [5 favorites]

We all remember the Fermi Paradox, yeah? I was just thinking the other day about how we really don't hear very much about it anymore.
posted by Smedly, Butlerian jihadi at 10:28 PM on November 8 [2 favorites]

re: "living in a post-Haber-Bosch world..."
The Man Who Killed Millions and Saved Billions - "Fritz Haber is the scientist who arguably most transformed the world."

but you know, sometimes stuff comes up...

also btw...
The Most Insane Weapon You Never Heard About - "At the height of the Cold War, a terrifying concept emerged: a bomb so powerful it wouldn't need to be dropped. Known as Project Sundial, this doomsday device would have left a 400-km radius in flames and plunged the world into darkness. It was a bomb that would destroy everything – not a weapon, but an apocalypse. How close did we come to pressing the button?" (Bulletin of the Atomic Scientists)
posted by kliuless at 10:50 PM on November 8 [1 favorite]

Fritz Haber The man who . . . saved billions.
errrm, not exactly? That claim is also made for Norman Borlaug lynch-pin of the Green Revolution. Haber, Borlaug and science changed the economic, ecological and agricultural conditions in a way that encouraged a billion subsistence farmers in the third world to try for another baby, so Borlaug could be more realistically named "The Man Who Created A Billion Lives", like some super-Shockley sperm-donor. Whatevs, back to the fertile crescent.

[Also Haber-Bosch brute-force fixing of N accounts for 1.4% of global carbon dioxide emissions and consumes 1% of the world's total energy production. ]
posted by BobTheScientist at 2:15 AM on November 9 [3 favorites]

Great post thanks. I really enjoy reading archaeology esp. when it interesects with climate.

Re Haber-Bosch, Vaclav Smil's 1997 Global Population and the Nitrogen Cycle [pdf link goes to Smil's own .com] is a good place to return to for the basics of why we're in this mess; Earth's natural N pool is sufficient for a stable pop. of <1.5 Billion.

Also the N is isotopically different from natural N and (among other effects) changes plant cell structure such that materials like roofing thatch grown with synthetic urea only last a tenth of the time of natural N grown reed or wheat stem (growing natural N thatch is a significan income stream for some organic farmers, including King Charles). Very little is known about the process as there seems to be no interest in funding understanding the underpinnings of our fake civilisation.
posted by unearthed at 8:40 AM on November 9 [7 favorites]

...so Borlaug could be more realistically named "The Man Who Created A Billion Lives", like some super-Shockley sperm-donor. Whatevs, back to the fertile crescent.

Well at least Elon is still giving his sperm away to all takers. Whatevs, all the way forward to Mars.
posted by y2karl at 10:54 AM on November 9

very interesting article. it's easy to forget that aside from the clear anthropogenic impact on climate cycles, nature has them too. a natural cycle of desiccation as we slide into the Destructoscene could be quite a force multiplier. yikes :\

1177 BC by Eric Cline examines a later Bronze Age Collapse that certainly affected the wider Mediterranean area. a fun read for the archaeology + climate change crowd.

a bit further afield, but also The Fate of Rome by Kyle Harper. Ancient History + climate change + emerging diseases. fun for the whole family!
posted by supermedusa at 11:45 AM on November 9 [1 favorite]

(the Eric Cline book is also available as a graphic...ah...whatever the nonfiction equivalent of a graphic novel is, for younger readers!)
posted by mittens at 4:29 PM on November 9 [2 favorites]

"Crop yields from organic farming are as much as 34% lower than those from comparable conventional farming practices"

In other words, we never more than triple yields through the use of pesticides and fertilizers made by Haber-Bosch. We grossly exagerate the importance of pesticide, so likely Haber-Bosch claims most of this benefit. Yet still, at best it less than triples yields? Alright, so where does modern agriculture really come from, if not Haber-Bosch?

Irrigation and transport seem vastly more important than Haber-Bosch, but especially irrigation. We developed civilization because a stable climate allowed relatively basic irrigation, after which civilizations improved irrigation technologies, enabled civilizations in more places.

"It’s not surprising that climate change has doomed so many populations, Blom says. After all, it was when weather patterns finally became predictable about 11,500 years ago that complex civilizations finally formed in the first place."

We've crazy advanced irrigation technology now, but as our climate breaks down irrigation become harder and harder in more places. I suppose transport means everyone gets this shock together.
posted by jeffburdges at 6:19 PM on November 11

Here's another link regarding changes in the Atlantic Meridional Overturning Circulation:

Meltwater from Greenland and the Arctic is weakening ocean circulation to speed up warming down south, model suggests

...Our climate has changed dramatically over the past 20 years. More rapid melting of the ice sheets will accelerate further disruption of the climate system.

This means we have even less time to stabilize the climate. So it is imperative that humanity acts to reduce emissions as fast as possible.

posted by y2karl at 9:46 PM on November 18 [1 favorite]