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#holocene

1 post1 participant0 posts today
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Radical Anthropology

This comment on #archaeological analysis based in GINI coefficients (fundamentally house space across a 1000 sites) focuses on inequality (or not) in the #Holocene

livescience.com/archaeology/in

But do NOT imagine that there were no #Pleistocene #civilisations. We became Homo sapiens, the symbolic species, thanks to #egalitarianism
And don't anyone try telling me this isn't civilisation! Subsequent 'civilisations' were those which maintained egalitarianism, the most politically complex human societies. 'Civil' society promotes equality, sharing and cooperation with strangers, and investment in childcare not warfare -- the exact opposite tendencies of today's fascism.

c.im/@RadicalAnthro/1133239907

Live Science · Did every civilization have inequality? New 10,000-year study reveals a surprising answer.By Ben Turner
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💧🌏 Greg Cocks

Atop The Oregon Cascades, [Research] Team Finds A Huge Buried Aquifer
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eurekalert.org/news-releases/1 <-- shared technical article
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doi.org/10.1073/pnas.241515512 <-- shared paper
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usgs.gov/centers/oregon-water- <-- shared USGS technical article, 2011, ‘McKenzie River Source Water Study’
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youtu.be/6R8e5HwGMwU?si=sniW4b <-- shared media video overview
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#GIS #spatial #mapping #model #modeling #water #hydrology #Oregon #Cascades #CascadeMountains #PNW #PacificNorthwest #volcanic #rocks #aquifer #waterresources #watermanagement #climatechange #snowpack #drought #spatialanalysis #CriticalZone #geohazards #geology #engineeringgeology #landscapes #weathering #bedrock #holocene #groundwater #structuralgeology #orogeny #remotesensing #geophysics #sampling #drilling #porosity #permability #tomography #lava #spring #seep #breccia #discharge #streams #runoff #precipitation #climate #rainfall #recharge

photo - Scientists examine a large-volume spring in young volcanic rocks of the McKenzie River watershed on the west side of the Cascade topographic crest that was monitored as part of this study. Credit: Benjamin Nash
map, photo and charts - (A) Electrical resistivity tomography of Olallie North Spring, which emerges along a flow contact of _25 ka Scott Mountain lava flows. Lateral variations correspond to spring discharge points along the lava flow basal breccia such as depicted in (B) (photo: Benjamin Nash). (C) Mean of total yearly range in discharge _Q divided by mean annual flow Qavg versus average upstream age for springs and streams. The horizontal line defines “spring-” versus “runoff-” dominated. (D) SD of yearly average summer discharge (June–September), normalized by Qavg, with CZ state shift labeled.
maps and chart - (A) Distribution of geothermal drill holes. Thin black circles’ radii scale with total logged length, and colors indicate the fraction of length for which dT=dz < 20_C/km (implying downward flux of meteoric water). Red circles are the fraction with inverted gradients (dT=dz < 0_C/km). The purple contour indicates bedrock ages <2 Ma, while stars mark Holocene age phreatomagmatic eruption vents. (B) Two example temperature-depth logs from deep wells in old and young bedrock. (C) Porosity (blue) and resistivity (orange) in the Santiam Pass drill hole SP 77-24. Dashed lines indicate low porosity at high measured resistivity. (D) Chemical weathering tracked by oxidation state of iron in the Santiam Pass drill hole. The green box indicates range of Quaternary High Cascades lavas (SI Appendix), indicating that much of the SP 77-24 hole has been oxidized.
maps and cross section - Oregon Cascades study site. (A) Topography, rivers (from USGS blue lines), stream gauges, lakes, and faults. Olallie North Spring (ONS) and HJ Andrews Experimental Forest (HJA) are labeled. (B) Surface bedrock ages (18), geothermal drill holes, and Quaternary volcanic vents (19). Labeled vents exhibited Holocene phreatomagmatic activity: Sand Mountain volcanic field (SMF), Blue Lake Crater (BLC), Twin Craters (TC). Gray areas are mapped as “Sedimentary deposits and rocks” in ref. 18. (C) Cross-section of swath topography and surface bedrock ages (N-S average of _4 km from Santiam Pass, pink box in panel A), with subsurface structures based on published geologic maps (SI Appendix). The proposed Critical Zone (CZ) state shift and physiographic “Western” and “High” Cascade provinces are labeled. (D) Temperature gradient versus depth in drill holes from panel (C). Near-isothermal or inverted temperature gradients define the “rain curtain.”
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anlomedad

The last time, today's warming rate happened was during deglaciation, see ice core from Greenland.
It was so fast that the AMOC stopped. Which also re-froze Scotland and Scandinavia for a while. Scotland was a wall of ice 800 m tall!

But the Earth's orbital cycles drove further warming, #AMOC restarted – and our stable #Holocene began.

The chart shows decadal average temperature in °C from Renland in East Greenland and a short contemporary time series from a weather station 600km further North at the coast in Danmarkshavn. To visualise the similar warming rates a little better, Danmarkshavn's data was copied in at the 2 previous periods of fast rising temperatures in Renland.
Noteworthy: the 2 steep warming periods took about 300 years each and covered first 10 and then 8 °C. Roughly 0.33°C per decade.
While Danmarkshavn saw a rise of 0.35 per decade since 1980.

Line chart with decadal average temperature in celsius from ice core at Renland, East Greenland and the decadal average temperature in celsius from Danmarkshavn, at the coast 600km North of Renland. Renland time series is shown from year -13,370 to 2000, common era. Danmarkshavn from 1950 to 2020 (December 2024). At -12,800, Renland's temperature rises from -31 to -19.6 by year -12530. Danmarkshavn's short temperature time series is plotted right next to this rise and shows the same amplitude: a rise of 1.4 degrees within 4 decades (preceded by a short drop). Renland's time series then shows a few downs and ups until year -10,960 when it drops from -23 to -29 in -10,680. The last, fast rise of 8 degrees celsius begins in -9,830 up to -9,610. Then the rise becomes more gradual and from -6990 stays at about -14 degrees celsius for 6 thousand years, after which a slow, gradual decline begins. The very end of the time series is a sharp increase of 1.4 degrees celsius within 3 decades. Source: Buizert et al 2018 GHCN weather station Danmarkshavn GL000004320
#Paleoclimate#Greenland
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Kris Inwood

Professor Peter Turchin outlines a vision for evidence-based big history, “The Great Holocene Transformation: What Complexity Science Tells Us about the Evolution of Complex Societies”, a plenary address to the 8th Asian Historical Economics Conference at Hong Kong University www.cqh.hku.hk

@economics @demography @socialscience @sociology @politicalscience @geography @anthropology @econhist @devecon @archaeodons @sts @SocArXivBot #history #histodons #glamsdons #complexity #Holocene

Professor Peter Turchin outlines a vision for evidence-based big history, “The Great Holocene Transformation: What Complexity Science Tells Us about the Evolution of Complex Societies”, a plenary address to the 8th Asian Historical Economics Conference at Hong Kong University www.cqh.hku.hk
Professor Peter Turchin outlines a vision for evidence-based big history, “The Great Holocene Transformation: What Complexity Science Tells Us about the Evolution of Complex Societies”, a plenary address to the 8th Asian Historical Economics Conference at Hong Kong University www.cqh.hku.hk
Replied in thread
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anlomedad

@rahmstorf

Does anyone here know how or when AMOC is restarted after a shutdown?
How it used to get restarted in past climate changes. And how that restart would play out under our unusual changed factors?

I was thinking that maybe, a restart requires all Milankovic cycles to sufficiently favour Northern Hemisphere. And the process would be that sufficiently warmer summer temperatures over the Northern North Atlantic manage to evaporate enough ocean water for it to become saltier – and that would kickstart convection in place, with strictly local conditions as the first engine.

All 3 Milankovic cycles sufficiently favouring Northern Hemisphere, that's in about 120,000 years....

#AMOC#Ocean#AMOCShutdown
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anlomedad

reuters.com/investigates/speci

Cool webstory by Reuters about future Iceland's and global volcanic eruptions to be triggered by retreating glaciers, when the weight of the ice is no longer keeping a lid on magma chambers.
Apart from neat writing, it's with video, lotsa photos, animated charts and everything one can think of to be included in #scicomm

tldr: yes, volcanic eruptions will increase with the retreat of glaciers. #Antarctica's volcanos too. #Earthquake activity has already been picking up in Iceland since 2021, also elsewhere in the #Arctic near glaciers, and around the globe.

It has happened before when Earth crawled out of the last #iceage into the #Holocene.

I might add: it happened not only at volcanos near glaciers. Rising #sealevel has triggered near-coastal volcanos, too, whether above or below the water. IIRC, a study on Stromboli proved it.

I personally think, #HungaTonga's eruption could have been one of the first submarine volcanos to have been triggered by #climateChange Another submarine volcano erupted near Japan in 2021 or 2022, forgot its name, starts with an O...
Not as huge an explosion like Hunga Tonga tho.

#paleoclimate#volcano#Iceland
Replied to Dr Micha Campbell
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anlomedad

@michcampbell

Interesting.
From what I recall from a few papers I read, the Mediterranean, or #MENA, experienced droughts in the 4.2ky event.

But figure 4 in the new literature review by #McKay et al 2024 shows a decidedly wet excursion for MENA: nature.com/articles/s41467-024

They do mention the #Mediterranean and say, it were a complex and not at all clear case whether a drought was gripping the region or not.

So I pulled #d18O from cave #speleothem in the database " #Sisal3 " and plotted all those with okay resolution during the 4.2ky event.
The time span of the selection goes from 8.5ky to 2ky, like in McKay's paper.
My cave selection goes from longitude -9° to 85°E.
Locations are in the Google map, with the info whether it was dryer🔴 or wetter🌀 at 4.2ky.

A 3-colour-coded heatmap for the 50th percentile of d18O shows orange as drought and blue as wet.
More info in the ALT texts.

Conclusion: the mediterranean DID get dryer in the 4.2ky event. 🙂 🖖

Figure 4 from the literature review paper McKay et al 2024 shows global maps for temperature and moisture, top row for the 8.2Ka event and bottom row for the 4.2ka event. In the 4.2ka event, moisture went up in Europe and MENA, with the sole exception of Egypt which was a little dryer.
Location of the caves in the heatmap. Meaning of the colours : the difference between the average from 4250 to 4050 BP over the average in the whole individual speleothem series. Blue is if the 4.2ky period was higher than the alltime average, meaning, the speleothem received more rain during this period compared to its alltime average. Red is dryer than usual. The red dots are so big because otherwise, they'd hide behind the blue dots in cases where speleothems in a single cave/location show the opposite evolution. (This happens very often actually, d18O from stalagmites in the same cave not at all corresponding to each other. I don't know how to deal with this phenomenon. It's the reason why I usually don't look at stalagmites anymore. Very sad. They often have such high resolution. :( )
Heatmap for d18O in speleothems. Orange is dryer, blue is wetter. Visible in the top row is only a part of the coordinates of the caves, first longitude, then a part of the latitude. Red cells are caves below the equator. The selection is from -9 to 85°E. The leftmost column are the years before present. Red is the range 4250 to 4050 BP. The year 4200 is highlighted in green and also by an empty row above it. The visible range here is from year 4,254 to 4,016 BP. The whole selection goes from 8,500 to 2,000 BP. Only those caves are shown that have an okay resolution around the 4.2ky event. Source is Sisal v3.
#paleoclimate#holocene#drought
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Dr Micha Campbell

The first paper for our paper club is this recent one from McKay et al., presenting a thorough investigation of the (supposed?) 4.2 ka event. I'd read it when it was published, but just went through again in more detail, and what a good paper. Robust stats (of course, from this group), and they do a really nice job of building the case. I hope the group enjoys it!

#palaeoclimate #paleoclimate #Holocene #Quaternary

nature.com/articles/s41467-024

NatureThe 4.2 ka event is not remarkable in the context of Holocene climate variability - Nature CommunicationsA study of more than 1000 paleoclimate datasets reveals that the ”4.2 ka event” is not a globally significant climate excursion, unlike the prominent 8.2 ka event. In the Holocene, site-level excursions are common, but global-scale events are rare.
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Eric Maugendre

Humans do not do climate change.
Some activities do climate change.

#Anthropocene
period during which human activities have impacted the environment enough to constitute a distinct geological change.

#biomass
living organisms, and the energy contained within them.

#ecosystem
community and interactions of living and nonliving things in an area.

#Holocene
began at the end of the last glacial period, about 10,000 years ago.

education.nationalgeographic.o @anthropocene @technique @climate@a.gup.pe @climate@slrpnk.net

education.nationalgeographic.orgAge of Man: Enter the AnthropoceneIt's a new name for a new geologic epoch-one defined by our own massive impact on the planet. That mark will endure in the geologic record long after our cities have crumbled.
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