Earth Chgs Ancient relic points to a turning point in Earth's history 42,000 years ago

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Ancient relic points to a turning point in Earth's history 42,000 years ago

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19 Feb 2021

Sherry Landow

Just like in The Hitchhiker’s Guide to the Galaxy, the answer was 42.

Aurora borealis above mountain peak

This dramatic paleoclimate change – which was hallmarked with widespread auroras – could help explain other evolutionary mysteries, like the extinction of Neandertals. Photo: Unsplash.

The temporary breakdown of Earth’s magnetic field 42,000 years ago sparked major climate shifts that led to global environmental change and mass extinctions, a new international study co-led by UNSW Sydney and the South Australian Museum shows.

This dramatic turning point in Earth’s history – laced with electrical storms, widespread auroras, and cosmic radiation – was triggered by the reversal of Earth’s magnetic poles and changing solar winds.

The researchers dubbed this danger period the ‘Adams Transitional Geomagnetic Event’, or ‘Adams Event’ for short – a tribute to science fiction writer Douglas Adams, who wrote in The Hitchhiker's Guide to the Galaxy that ‘42’ was the answer to life, the universe, and everything.
The findings are published today in Science.

“For the first time ever, we have been able to precisely date the timing and environmental impacts of the last magnetic pole switch,” says Chris Turney, a professor at UNSW Science and co-lead author of the study.
A section of the ancient Ngāwhā kauri log lying on its side

This ancient kauri tree found in Ngāwhā, New Zealand, was alive during the Adams Event. Photo: Nelson Parker (www.nelsonskaihukauri.co.nz)
“The findings were made possible with ancient New Zealand kauri trees, which have been preserved in sediments for over 40,000 years.

“Using the ancient trees we could measure, and date, the spike in atmospheric radiocarbon levels caused by the collapse of Earth’s magnetic field.”

While scientists already knew the magnetic poles temporarily flipped around 41-42,000 years ago (known as the ‘Laschamps Excursion’), they didn’t know exactly how it impacted life on Earth – if at all.

But the researchers were able to create a detailed timescale of how Earth’s atmosphere changed over this time by analysing rings on the ancient kauri trees.

“The kauri trees are like the Rosetta Stone, helping us tie together records of environmental change in caves, ice cores and peat bogs around the world,” says co-lead Professor Alan Cooper, Honorary Researcher at the South Australian Museum.

The researchers compared the newly-created timescale with records from sites across the Pacific and used it in global climate modelling, finding that the growth of ice sheets and glaciers over North America and large shifts in major wind belts and tropical storm systems could be traced back to the Adams Event.

One of their first clues was that megafauna across mainland Australia and Tasmania went through simultaneous extinctions 42,000 years ago.

“This had never seemed right, because it was long after Aboriginal people arrived, but around the same time that the Australian environment shifted to the current arid state,” says Prof. Cooper.

The paper suggests that the Adams Event could explain a lot of other evolutionary mysteries, like the extinction of Neandertals and the sudden widespread appearance of figurative art in caves around the world.

“It’s the most surprising and important discovery I’ve ever been involved in,” says Prof. Cooper.

View: https://youtu.be/Qs1dLe3GsQY



Watch as Stephen Fry brings to life the story of the 'Adams event'. Video: UNSW Sydney.

The perfect (cosmic) storm
The magnetic north pole – that is, the direction a compass needle points to – doesn’t have a fixed location. It usually wobbles close to the North Pole (the northern-most point of Earth’s axis) over time due to dynamic movements within the Earth’s core, just like the magnetic south pole.

Sometimes, for reasons that aren’t clear, the magnetic poles’ movements can be more drastic. Around 41,000-42,000 years ago they swapped places entirely.

“The Laschamps Excursion was the last time the magnetic poles flipped,” says Prof. Turney. “They swapped places for about 800 years before changing their minds and swapping back again.”

Until now, scientific research has focused on changes that happened while the magnetic poles were reversed, when the magnetic field was weakened to about 28 per cent of its present-day strength.

But according to the team’s findings, the most dramatic part was the lead-up to the reversal, when the poles were migrating across the Earth.
“Earth’s magnetic field dropped to only 0-6 per cent strength during the Adams Event,” says Prof. Turney.

“We essentially had no magnetic field at all – our cosmic radiation shield was totally gone.”

During the magnetic field breakdown, the Sun experienced several ‘Grand Solar Minima’ (GSM), long-term periods of quiet solar activity.
Even though a GSM means less activity on the Sun’s surface, the weakening of its magnetic field can mean more space weather – like solar flares and galactic cosmic rays – could head Earth’s way.

“Unfiltered radiation from space ripped apart air particles in Earth’s atmosphere, separating electrons and emitting light – a process called ionisation,” says Prof. Turney.

“The ionised air ‘fried’ the Ozone layer, triggering a ripple of climate change across the globe.”
Aurora over icy landscape

From auroras to lightning storms, the sky would have put on quite a show during the Adams Event. Photo: Unsplash.

Into the caves
Dazzling light shows would have been frequent in the sky during the Adams Event.

Aurora borealis and aurora australis, also known as the northern and southern lights, are caused by solar winds hitting the Earth’s atmosphere.

Usually confined to the polar northern and southern parts of the globe, the colourful sights would have been widespread during the breakdown of Earth’s magnetic field.

“Early humans around the world would have seen amazing auroras, shimmering veils and sheets across the sky,” says Prof. Cooper.

Ionised air – which is a great conductor for electricity – would have also increased the frequency of electrical storms.

“It must have seemed like the end of days,” says Prof. Cooper.

The researchers theorise that the dramatic environmental changes may have caused early humans to seek more shelter. This could explain the sudden appearance of cave art around the world roughly 42,000 years ago.

“We think that the sharp increases in UV levels, particularly during solar flares, would suddenly make caves very valuable shelters,” says Prof. Cooper. “The common cave art motif of red ochre handprints may signal it was being used as sunscreen, a technique still used today by some groups.

“The amazing images created in the caves during this time have been preserved, while other art out in open areas has since eroded, making it appear that art suddenly starts 42,000 years ago.”
Handprints outlined by red ochre on a cave wall

The centre of this cave art from El Castillo Cave in Spain is believed to be almost 42,000 years old – the same age as the Adams Event. Photo: Paul Pettitt, courtesy Gobierno de Cantabria.

Uncovering ancient clues
These findings come two years after a particularly important ancient kauri tree was uncovered at Ngāwhā, Northland.
The massive tree – with a trunk spanning over two and a half metres – was alive during the Laschamps.

“Like other entombed kauri logs, the wood of the Ngāwhā tree is so well preserved that the bark is still attached,” says UNSW’s Dr Jonathan Palmer, a specialist in dating tree-rings (dendrochronology). Dr Palmer studied cross sections of the trees at UNSW Science’s Chronos 14Carbon-Cycle Facility.

Using radiocarbon dating – a technique to date ancient relics or events – the team tracked the changes in radiocarbon levels during the magnetic pole reversal. This data was charted alongside the trees’ annual growth rings, which acts as an accurate, natural timestamp.

The new timescale helped reveal the picture of this dramatic period in Earth’s history. The team were able to reconstruct the chain of environmental and extinction events using climate modelling.

“The more we looked at the data, the more everything pointed to 42,” says Prof. Turney. “It was uncanny.
“Douglas Adams was clearly on to something, after all.”

View: https://youtu.be/NSig4MyLQ0o



The ancient kauri trees were key to the findings, explain Prof. Chris Turney and Prof. Alan Cooper. Video: UNSW Sydney.

An accelerant like no other
While the magnetic poles often wander, some scientists are concerned about the current rapid movement of the north magnetic pole across the Northern Hemisphere.

“This speed – alongside the weakening of Earth’s magnetic field by around nine per cent in the past 170 years – could indicate an upcoming reversal,” says Prof. Cooper.

“If a similar event happened today, the consequences would be huge for modern society. Incoming cosmic radiation would destroy our electric power grids and satellite networks.”

Prof. Turney says the human-induced climate crisis is catastrophic enough without throwing major solar changes or a pole reversal in the mix.

“Our atmosphere is already filled with carbon at levels never seen by humanity before,” he says. “A magnetic pole reversal or extreme change in Sun activity would be unprecedented climate change accelerants.

“We urgently need to get carbon emissions down before such a random event happens again.”

This work was made possible by funding from an Australian Research Council Discovery Project Grant, support from Ngāpuhi iwi and Top Energy, the University of Waikato Radiocarbon Laboratory, and many other national and international partners.
 

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Research Article

A global environmental crisis 42,000 years ago

  1. View ORCID ProfileAlan Cooper1,2,*,,
  2. View ORCID ProfileChris S. M. Turney3,*,,
  3. View ORCID ProfileJonathan Palmer3,
  4. View ORCID ProfileAlan Hogg4,
  5. View ORCID ProfileMatt McGlone5,
  6. View ORCID ProfileJanet Wilmshurst5,6,
  7. View ORCID ProfileAndrew M. Lorrey7,
  8. View ORCID ProfileTimothy J. Heaton8,
  9. View ORCID ProfileJames M. Russell9,
  10. View ORCID ProfileKen McCracken10,
  11. View ORCID ProfileJulien G. Anet11,
  12. View ORCID ProfileEugene Rozanov12,13,14,
  13. View ORCID ProfileMarina Friedel12,
  14. View ORCID ProfileIvo Suter15,
  15. View ORCID ProfileThomas Peter12,
  16. View ORCID ProfileRaimund Muscheler16,
  17. View ORCID ProfileFlorian Adolphi17,
  18. View ORCID ProfileAnthony Dosseto18,
  19. View ORCID ProfileJ. Tyler Faith19,
  20. View ORCID ProfilePavla Fenwick20,
  21. View ORCID ProfileChristopher J. Fogwill21,
  22. View ORCID ProfileKonrad Hughen22,
  23. View ORCID ProfileMathew Lipson23,
  24. View ORCID ProfileJiabo Liu24,
  25. View ORCID ProfileNorbert Nowaczyk25,
  26. Eleanor Rainsley21,
  27. View ORCID ProfileChristopher Bronk Ramsey26,
  28. View ORCID ProfilePaolo Sebastianelli27,
  29. View ORCID ProfileYassine Souilmi28,
  30. View ORCID ProfileJanelle Stevenson29,30,
  31. View ORCID ProfileZoë Thomas3,
  32. View ORCID ProfileRaymond Tobler28,
  33. View ORCID ProfileRoland Zech31

See all authors and affiliations

Science 19 Feb 2021:
Vol. 371, Issue 6531, pp. 811-818
DOI: 10.1126/science.abb8677


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Reversing the field
Do terrestrial geomagnetic field reversals have an effect on Earth's climate? Cooper et al. created a precisely dated radiocarbon record around the time of the Laschamps geomagnetic reversal about 41,000 years ago from the rings of New Zealand swamp kauri trees. This record reveals a substantial increase in the carbon-14 content of the atmosphere culminating during the period of weakening magnetic field strength preceding the polarity switch. The authors modeled the consequences of this event and concluded that the geomagnetic field minimum caused substantial changes in atmospheric ozone concentration that drove synchronous global climate and environmental shifts.
Science, this issue p. 811
Abstract
Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.
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Housecarl

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Posted for fair use.....

Business Insider
Neanderthals died out after Earth's magnetic poles flipped, causing a climate crisis 42,000 years ago, a study says





Aria Bendix
Sat, February 20, 2021, 4:32 AM

  • Earth's magnetic poles flipped 42,000 years ago, which may have triggered a global climate crisis, a new study found.
  • The resulting changes in temperatures and radiation levels may have killed off many large mammals.
  • The event may have ultimately contributed to the extinction of Neanderthals.
Earth saw a lot of commotion when its magnetic poles flipped 42,000 years ago.

Scientists have known about the flip since the late 1960s. Earth's magnetic poles aren't static - they're generated by electric currents from the planet's liquid outer core, which is constantly in motion. As of late, Earth's magnetic North pole has wandered considerably on a path toward northern Russia.

But for the most part, scientists didn't think the last pole flip had a major environmental impact. Sure, the planet's magnetic field got weaker, allowing more cosmic rays to penetrate the atmosphere, but plant and animal life wasn't known to have been greatly affected.

A new study now suggests a more dramatic phenomenon occurred: The additional cosmic rays may have depleted ozone concentrations, opening the floodgates for more ultraviolet radiation in the atmosphere. Shifting weather patterns may have expanded the ice sheet over North America and dried out Australia, prompting the extinction of many large mammal species. A solar storm, meanwhile, might have driven ancient humans to seek shelter in caves.

As competition for resources grew, our closest extinct human relative, Neanderthals, may have died out.

"It would have been an incredibly scary time, almost like the end of days," Chris Turney, an Earth scientist at the University of New South Wales, said in a video describing the new research.

Scientists have not come to agree on a definitive theory about why Neanderthals disappeared. Some research suggests their extinction happened naturally, as Neanderthals inbred with modern humans or the population became too small to hunt, mate, and raise children. Other scientists have posited that Neanderthals may have been out-competed for resources as modern humans started to populate Europe.

But it's probably no coincidence that Neanderthals died out following a major shift of Earth's magnetic poles, Turney's study suggests.

"It was only when you started talking between different areas of science, you could see the connections," his co-author, Alan Cooper, said. "Before that, none of the different fields had worked out 42 [42,000 years ago] was the key event."

Ancient trees and caves hold clues about a possible climate disaster
A scientist takes measurements for the archaeo-magnetic survey in the Bruniquel Cave in southwestern France in this undated handout photo after the discovery there of mysterious ring-shaped structures fashioned about 176,500 years ago by Neanderthals. Etienne FABRE - SSAC/Handout via Reuters

A scientist takes measurements in the Bruniquel Cave in southwestern France. Thomson Reuters
To find out what happened to Earth's climate 42,000 years ago, scientists asked a native New Zealander who was alive at the time: the ancient kauri tree. The tree's rings serve as a record of radiocarbon levels - a radioactive isotope - in the atmosphere over tens of thousands of years. Indeed, the rings showed evidence of rising radiocarbon at the time when the magnetic fields flipped, an event known as the "Laschamps excursion."

The event isn't unique in the history of our planet: The British Geological Survey estimates that four or five pole flips occur every million years.

During these reversals, the magnetic shield that protects our planet from solar wind (charged particles streaming off the sun) gets weaker. Earth's magnetic North and South poles - not to be confused with the planet's northernmost and southernmost geographic points - switch places.

The Laschamps excursion, the most recent example of this magnetic flip, likely took place over a period of 1,000 years. That's a blip in Earth's lifetime, but long enough to alter the fates of those living on the planet.

"In that process of flipping from North to South and South to North, effectively the Earth's magnetic field almost disappeared," Turney said. "And it opened the planet up to all these high-energy particles from outer space."

If the sun spewed extra-high levels of radiation in a solar storm during that time, Neanderthals may have needed to seek cover.

Indeed, the Laschamps excursion coincided with a rise in cave use across Europe and Southeast Asia. In particular, researchers have found red ocher handprints in the regions' caves that date back some 40,000 years. According to the new study, this pigment could have served as an ancient form of sunscreen.

Neanderthal study

Red ocher handprints in Spain's El Castillo cave may represent the use of an ancient form of sunscreen. Paul Pettitt, Gobierno de Cantabria
Another magnetic reversal could be 'imminent'
Not all researchers are convinced by Turney and Cooper's analysis. Chris Stringer, an anthropologist at the Natural History Museum in London, told The Guardian that although the Laschamps excursion could have contributed to Neanderthals' demise, it's hard to know exactly when they died out.

"They did survive longer and ranged more widely than just Europe, and we have a very poor fix on the timing of their final disappearance across swathes of Asia," Stringer said.

James Channell, a geologist at the University of Florida, told NPR that historical records of ice cores dating back 42,000 years don't indicate a global climate crisis. Still, he added, "there does appear to be a linkage" between the extinction of large mammals and the weakening of Earth's magnetic field.

At the very least, the new study offers a hint about what could happen if magnetic north and south flip again.

Scientists know that Earth's magnetic field has weakened about 9% in the past 170 years. The magnetic North pole has also been drifting more rapidly since the 1990s, at a rate of 30 to 40 miles per year.

This has "increased speculation that a field reversal may be imminent," the researchers wrote. Such an event could potentially topple power grids and satellite networks. An increase in radiation could also expose more people to diseases like cancer.

But scientists suspect that any possible magnetic reversal would be in its early stages. Earth's magnetic field is still far stronger than it was the last time the poles flipped.

Read the original article on Business Insider
 

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Posted for fair use.....

Business Insider
Neanderthals died out after Earth's magnetic poles flipped, causing a climate crisis 42,000 years ago, a study says





Aria Bendix
Sat, February 20, 2021, 4:32 AM

  • Earth's magnetic poles flipped 42,000 years ago, which may have triggered a global climate crisis, a new study found.
  • The resulting changes in temperatures and radiation levels may have killed off many large mammals.
  • The event may have ultimately contributed to the extinction of Neanderthals.
Earth saw a lot of commotion when its magnetic poles flipped 42,000 years ago.

Scientists have known about the flip since the late 1960s. Earth's magnetic poles aren't static - they're generated by electric currents from the planet's liquid outer core, which is constantly in motion. As of late, Earth's magnetic North pole has wandered considerably on a path toward northern Russia.

But for the most part, scientists didn't think the last pole flip had a major environmental impact. Sure, the planet's magnetic field got weaker, allowing more cosmic rays to penetrate the atmosphere, but plant and animal life wasn't known to have been greatly affected.

A new study now suggests a more dramatic phenomenon occurred: The additional cosmic rays may have depleted ozone concentrations, opening the floodgates for more ultraviolet radiation in the atmosphere. Shifting weather patterns may have expanded the ice sheet over North America and dried out Australia, prompting the extinction of many large mammal species. A solar storm, meanwhile, might have driven ancient humans to seek shelter in caves.

As competition for resources grew, our closest extinct human relative, Neanderthals, may have died out.

"It would have been an incredibly scary time, almost like the end of days," Chris Turney, an Earth scientist at the University of New South Wales, said in a video describing the new research.

Scientists have not come to agree on a definitive theory about why Neanderthals disappeared. Some research suggests their extinction happened naturally, as Neanderthals inbred with modern humans or the population became too small to hunt, mate, and raise children. Other scientists have posited that Neanderthals may have been out-competed for resources as modern humans started to populate Europe.

But it's probably no coincidence that Neanderthals died out following a major shift of Earth's magnetic poles, Turney's study suggests.

"It was only when you started talking between different areas of science, you could see the connections," his co-author, Alan Cooper, said. "Before that, none of the different fields had worked out 42 [42,000 years ago] was the key event."

Ancient trees and caves hold clues about a possible climate disaster
A scientist takes measurements for the archaeo-magnetic survey in the Bruniquel Cave in southwestern France in this undated handout photo after the discovery there of mysterious ring-shaped structures fashioned about 176,500 years ago by Neanderthals. Etienne FABRE - SSAC/Handout via Reuters

A scientist takes measurements in the Bruniquel Cave in southwestern France. Thomson Reuters
To find out what happened to Earth's climate 42,000 years ago, scientists asked a native New Zealander who was alive at the time: the ancient kauri tree. The tree's rings serve as a record of radiocarbon levels - a radioactive isotope - in the atmosphere over tens of thousands of years. Indeed, the rings showed evidence of rising radiocarbon at the time when the magnetic fields flipped, an event known as the "Laschamps excursion."

The event isn't unique in the history of our planet: The British Geological Survey estimates that four or five pole flips occur every million years.

During these reversals, the magnetic shield that protects our planet from solar wind (charged particles streaming off the sun) gets weaker. Earth's magnetic North and South poles - not to be confused with the planet's northernmost and southernmost geographic points - switch places.

The Laschamps excursion, the most recent example of this magnetic flip, likely took place over a period of 1,000 years. That's a blip in Earth's lifetime, but long enough to alter the fates of those living on the planet.

"In that process of flipping from North to South and South to North, effectively the Earth's magnetic field almost disappeared," Turney said. "And it opened the planet up to all these high-energy particles from outer space."

If the sun spewed extra-high levels of radiation in a solar storm during that time, Neanderthals may have needed to seek cover.

Indeed, the Laschamps excursion coincided with a rise in cave use across Europe and Southeast Asia. In particular, researchers have found red ocher handprints in the regions' caves that date back some 40,000 years. According to the new study, this pigment could have served as an ancient form of sunscreen.

Neanderthal study

Red ocher handprints in Spain's El Castillo cave may represent the use of an ancient form of sunscreen. Paul Pettitt, Gobierno de Cantabria
Another magnetic reversal could be 'imminent'
Not all researchers are convinced by Turney and Cooper's analysis. Chris Stringer, an anthropologist at the Natural History Museum in London, told The Guardian that although the Laschamps excursion could have contributed to Neanderthals' demise, it's hard to know exactly when they died out.

"They did survive longer and ranged more widely than just Europe, and we have a very poor fix on the timing of their final disappearance across swathes of Asia," Stringer said.

James Channell, a geologist at the University of Florida, told NPR that historical records of ice cores dating back 42,000 years don't indicate a global climate crisis. Still, he added, "there does appear to be a linkage" between the extinction of large mammals and the weakening of Earth's magnetic field.

At the very least, the new study offers a hint about what could happen if magnetic north and south flip again.

Scientists know that Earth's magnetic field has weakened about 9% in the past 170 years. The magnetic North pole has also been drifting more rapidly since the 1990s, at a rate of 30 to 40 miles per year.

This has "increased speculation that a field reversal may be imminent," the researchers wrote. Such an event could potentially topple power grids and satellite networks. An increase in radiation could also expose more people to diseases like cancer.

But scientists suspect that any possible magnetic reversal would be in its early stages. Earth's magnetic field is still far stronger than it was the last time the poles flipped.

Read the original article on Business Insider

News flash we didn’t all die out, class 1A knuckle dragger here!
 

Housecarl

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Posted for fair use.....

Earth’s Magnetic Field Reversal 42,000 Years Ago Triggered a Global Environmental Crisis
TOPICS:American Association for the Advancement of ScienceGeologyGeophysicsPopular

By American Association for the Advancement of Science February 19, 2021


Earth Core Magnetic Field

Nearly 42,000 years ago, when Earth’s magnetic fields reversed, this triggered major environmental changes, extinction events, and long-term changes in human behavior, a new study reports.

The findings, made possible by a new radiocarbon record derived from New Zealand’s ancient kauri trees, raise important questions about the evolutionary impacts of geomagnetic reversals and excursions throughout the deeper geological record, the authors say.

“Before this work,” says author Chris Turney in a related video, “we knew there were a lot of things happening around the world at 42,000 years ago, but we didn’t know precisely how… For the first time, we’ve been able to precisely date what happened when Earth’s magnetic fields last flipped.”

Written in the geological record are numerous instances where the planet’s magnetic poles flipped. Today, such an event would almost certainly wreak havoc with modern electronic and satellite technologies. However, the potential environmental impacts of such events are virtually unknown.

The most recent major magnetic inversion, the Laschamps excursion, a relatively short-lived geomagnetic event that occurred ~41,000 years ago, provides one of the best opportunities to study the potential impacts of extreme changes to Earth’s magnetic field. However, despite compelling evidence from several paleoenvironmental records that suggest it coincided with significant environmental and ecological changes, the ability to precisely characterize this event and determine its role — if any — in contemporaneous global changes has been limited by an uncertain radiocarbon calibration for the period.

In this study, Turney, Alan Cooper, and colleagues present a new, precisely dated atmospheric radiocarbon record derived from the tree rings of ancient kauri trees preserved for millennia in New Zealand wetlands. Like a missing keystone, this new record allowed the authors to better align other global radiocarbon and ice core records with the Laschamps.

Cooper et al. identified a significant increase in atmospheric radiocarbon during the period of weakening magnetic field strength that preceded polarity reversal. By modeling the consequences of this increase, they found that the geomagnetic field minimum, when Earth’s magnetic field was estimated to be only ~6% of current levels, triggered substantial changes in atmospheric ozone concentration and circulation.

These shifts may have caused synchronous global climate and environmental changes observed in other climate records that occurred ~42,000 years ago. The discovery that geomagnetic field fluctuations can affect atmospheric temperature and circulation on a global scale provides a model for understanding anomalous and sudden paleoenvironmental shifts, the authors say.

Reference: “A global environmental crisis 42,000 years ago” by Alan Cooper, Chris S. M. Turney, Jonathan Palmer, Alan Hogg, Matt McGlone, Janet Wilmshurst, Andrew M. Lorrey, Timothy J. Heaton, James M. Russell, Ken McCracken, Julien G. Anet, Eugene Rozanov, Marina Friedel, Ivo Suter, Thomas Peter, Raimund Muscheler, Florian Adolphi, Anthony Dosseto, J. Tyler Faith, Pavla Fenwick, Christopher J. Fogwill, Konrad Hughen, Mathew Lipson, Jiabo Liu, Norbert Nowaczyk, Eleanor Rainsley, Christopher Bronk Ramsey, Paolo Sebastianelli, Yassine Souilmi, Janelle Stevenson, Zoë Thomas, Raymond Tobler and Roland Zech, 19 February 2021, Science.
DOI: 10.1126/science.abb8677
 

Housecarl

On TB every waking moment
Posted for fair use.....

Ancient kauri trees capture last collapse of Earth’s magnetic field
By Paul VoosenFeb. 18, 2021 , 2:00 PM

Several years ago, workers breaking ground for a power plant in New Zealand unearthed a record of a lost time: a 60-ton trunk from a kauri tree, the largest tree species in New Zealand. The tree, which grew 42,000 years ago, was preserved in a bog and its rings spanned 1700 years, capturing a tumultuous time when the world was turned upside down—at least magnetically speaking.

Radiocarbon levels in this and several other pieces of wood chart a surge in radiation from space, as Earth’s protective magnetic field weakened and its poles flipped, a team of scientists reports today in Science. By modeling the effect of this radiation on the atmosphere, the team suggests Earth’s climate briefly shifted, perhaps contributing to the disappearance of large mammals in Australia and Neanderthals in Europe. “We’re only scratching the surface of what geomagnetic change has done,” says Alan Cooper, an ancient DNA researcher at the South Australian Museum and one of the lead authors of the study.

The study not only nails in fine detail the timing and magnitude of the magnetic swap, the most recent in Earth’s history, but is also among the first to make a credible, though speculative, case that these flips can affect the global climate, says Quentin Simon, a paleomagnetist at the European Center for Research and Teaching in Environmental Geoscience in Aix-en-Provence, France. But some paleoclimate scientists are skeptical of the team’s broader claims, saying other records show few traces of climate upheaval.

Earth’s magnetic field is created by the flow of molten iron in the outer core, which is prone to chaotic swings that not only weaken the field, but also cause the poles to wander and sometimes flip entirely. The magnetic orientations of minerals in rock record long-lasting reversals, but can’t capture the details of a flip lasting hundreds of years, like the one 42,000 years ago.

Radioactive carbon-14, however, can mark these shorter fluctuations. The isotope is produced when cosmic rays—charged particles from outer space—slip past the magnetic field and strike the atmosphere. It is taken up by living things, and its specific half-life makes it a standard clock. The team used radiocarbon to date the kauri wood by lining it up with accurate, but coarse, radiocarbon cave records from China. And by measuring finer carbon-14 changes in the rings, they tracked how its production varied over 40-year intervals, as the magnetic field ebbed and surged. “It’s just amazing you can do this back 42,000 years ago,” says Lawrence Edwards, a geochemist at the University of Minnesota, Twin Cities, who worked on the Chinese cave records.

Spikes in radiocarbon indicated the magnetic field weakened to some 6% of its present day strength by 41,500 years ago. At that point the poles flipped and the field recovered some strength, before crashing and flipping back 500 years later. Cooper notes that not only was Earth’s cosmic ray shield down; the Sun’s was, too. Evidence from ice cores suggests that, around this same time, the Sun was experiencing several “grand minima”—episodes of low magnetic activity. The resulting cosmic ray assault charged the atmosphere to a level that would have knocked out today’s power grid and created aurorae in the subtropics, Cooper says. “What happens when the atmosphere is that ionized?” he asks. “God only knows.” (The paper is the first Cooper has led since he was fired in 2019 from the University of Adelaide following allegations that he bullied staff and students; Cooper has denied the allegations.)

To explore the consequences, the team ran a climate model, which suggested the cosmic ray bombardment would have eroded the ozone layer, reducing the heat it normally captures from ultraviolet rays. The high altitude cooling would have changed wind flows, which in turn may have led to “drastic changes” on the surface, including a cooler North America and warmer Europe, says Marina Friedel, a team member and doctoral student in stratospheric chemistry at ETH Zurich.

This is where other scientists say the study gets too speculative. Ice cores from Greenland and Antarctica that span the past 100,000 years capture stark temperature swings every few thousand years. But they show no shifts 42,000 years ago. A few Pacific Ocean records do show swings. But even if the shift occurred mostly in the tropics, as Cooper and colleagues suggest, it should be seen in the ice, says Anders Svensson, a glaciologist at the University of Copenhagen. “We just don’t see that.”

The study team goes further to argue that a climate shift could account for a spate of curious events 42,000 years ago. Most notably, large mammals in Australia went extinct around that time. Neanderthals vanished from Europe, and elaborate cave paintings began to appear in Europe and Asia. Still, neither milestone in human evolution lines up well with the flip 42,000 years ago, and neither was sudden, says Thomas Higham, an archaeologist and radiocarbon expert at the University of Oxford. Linking them to the field reversal, he says, “seems to me to be pushing the evidence too far.”

*Correction, 19 February, 1 p.m.: A previous version of this story misstated the ancient climatic shifts for Europe and North America based on the team’s model.

Posted in:

doi:10.1126/science.abh1456

Paul Voosen

Paul Voosen
Paul Voosen is a staff writer who covers Earth and planetary science.
 

Oreally

Veteran Member
Links to those articles?
follow this guy, Jean


he is an amateur scientist who has developed and placed instruments he has designed and built all over the globe that are tracking the north pole's movement, along with Muon decay measurements ( relates to the amount of cosmic rays getting to the earth's surface..significant )along with takes from 'official' sites he follows.

a few weeks back he had one vid that showed the movement of the NP over the past 75 years according to NASA, plotted on Google Earth.

amazing.

also he has demonstrated with a simple apparatus, how and when there could be an 'event'...he thinks the tipping point is only 2 1/4 years away, or summer 2023.

YMMV
 

raven

Has No Life - Lives on TB
Today kids we have learned that magnetic pole shifts cause catastrophic climate change and mass extinction.
But its ok because we were the fittest and survived.

But wait, the poles are once again shifting . . .
And you caused it
 

packyderms_wife

Neither here nor there.
follow this guy, Jean


he is an amateur scientist who has developed and placed instruments he has designed and built all over the globe that are tracking the north pole's movement, along with Muon decay measurements ( relates to the amount of cosmic rays getting to the earth's surface..significant )along with takes from 'official' sites he follows.

a few weeks back he had one vid that showed the movement of the NP over the past 75 years according to NASA, plotted on Google Earth.

amazing.

also he has demonstrated with a simple apparatus, how and when there could be an 'event'...he thinks the tipping point is only 2 1/4 years away, or summer 2023.

YMMV
Or 2030 at the latest? Just asking since the top talking bobble heads keep screeching about the year 2030 and that we're all gonna die but they never come out and say why.
 

Mtsilverback

Senior Member
I found this really interesting and enlightening. He gets into the math of earths cosmic cycles and how it periodically results in world wide destruction, to keep on topic with OP, however there is much more significant repeating numbers presented.

HIDDEN MATHEMATICS - Randall Carlson - Ancient Knowledge of Space, Time & Cosmic Cycles

Run time : 2:02:29

View: https://www.youtube.com/watch?v=R7oyZGW99os
 

inskanoot

Veteran Member
I found this really interesting and enlightening. He gets into the math of earths cosmic cycles and how it periodically results in world wide destruction, to keep on topic with OP, however there is much more significant repeating numbers presented.

HIDDEN MATHEMATICS - Randall Carlson - Ancient Knowledge of Space, Time & Cosmic Cycles

Run time : 2:02:29

View: https://www.youtube.com/watch?v=R7oyZGW99os
Wow! I’m halfway through. Fascinating, but what if you are not using base 10?
 

Mtsilverback

Senior Member
I was thinking the same thing when I first watched this video. Unfortunately, with personal regret, my math skills are not up to it.
 

jward

passin' thru
Anton is quickly making his way to Ian, o' forgotten weapons, acclaim, with me.

..still, I wish he'd gone ahead and told me more about all these ways we have to
recreate magnetic fields, coz I dunno nuthin' bout that...

woulda liked more on the otjize stuff too- sunscreen ->red hand prints sounds
reasonable i reckon, but all the ideas explaining the colours and appearance o'
the prints do :: shrug :: cases made for it being symbolic n for war/life / coming
of age make as much sense.
 

jward

passin' thru
Pretty sure that 2030 is coz they had to bump the 2020 out, knowing there was no way no how they could keep that shell game going with that earlier date :rolleyes:

..dunno if Hutton is still 'round, but he used to track volcanic indicators n magnetosphere flux, solar spots etc- though his interest was verifying esoteric sources of info, his science was solid IIRC

Or 2030 at the latest? Just asking since the top talking bobble heads keep screeching about the year 2030 and that we're all gonna die but they never come out and say why.
 
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