A professor of geological sciences at Ohio State and a researcher with the Byrd Polar Research Center, Thompson points to markers in numerous records suggesting that the climate was altered suddenly some 5,200 years ago with severe impacts.
Carbon dating tests indicated the plant had been buried in the ice for about 5,200 years. That suggests that the climate had shifted suddenly to capture the plant and preserve it without killing it.
The date is significant because other abrupt changes in climate from around the world — such as the shift of the Sahara from a habitable region to a barren desert — also occurred around the same time. Thompson doesn’t know what happened to cause a plant to freeze in time, but one hypothesis is that fluctuations in solar output may be to blame.
Evidence shows that about 5,200 years ago, solar energy from the sun dropped sharply and then surged over a short period. This huge flux may have triggered unusually strong winters in Peru that suddenly buried plants in snow and droughts that laid waste to the Sahara.
strong evidence for an abrupt mid-Holocene climate event that marked the transition from early Holocene (pre-5,000-yr-B.P.) conditions to cooler, late Holocene (post-5,000-yr-B.P.) conditions. This abrupt event, ≈5,200 yr ago, was widespread and spatially coherent through much of the tropics and was coincident with structural changes in several civilizations. These three lines of evidence argue that the present warming and associated glacier retreat are unprecedented in some areas for at least 5,200 yr.
Climate Change: The Evidence and Our Options - Perspectives on Ocean Science
This is a fascinating lecture - Lonnie says how he met Thor Heyerdahl - who wondered WHY both the Mayan and Hindu calendars start at the same time - around 3200 BCE.... and Lonnie has found out INDEED there was abrupt climate change at that time...
Thor Heyerdahl (Norwegian pronunciation: [tuːr ˈhæ̀ɪəɖɑːl]; 6 October 1914 – 18 April 2002) was a Norwegian adventurer and ethnographer with a background in zoology, botany and geography.
Abrupt tropical climate change: Past and present
The average of eight accelerator mass spectrometry 14C dates from two different laboratories places the calendar age of this plant deposit at 5,138 (±45) yr B.P. (Table 1). The recently exposed plant deposit provides strong evidence that temperatures were warmer in this region before 5.1 thousand years (ka) B.P. and that the current retreat of Quelccaya is unprecedented for the last 5 millennia.
Mounting evidence from diverse archives suggests the occurrence of an abrupt “cold snap” just before the onset of the prolonged cooler late Holocene that lasted nearly 5 ka. The Kilimanjaro ice core δ18O record (Fig. 8B) shows that cooler conditions dominated in East Africa from ≈6.2 to 5.2 ka, when conditions cooled abruptly, concomitant with the onset of much drier conditions (8). The transition from wet to dry conditions ≈5.2 ka is recorded by changes in the water balance in many African lakes (36). Concurrently, global atmospheric CH4 concentrations recorded in both Greenland (37) and Antarctica (38) were at their lowest Holocene levels (Fig. 8D). With the abrupt onset of cool, wet conditions, the advancing glaciers in the Alps covered and preserved the “man from the Hauslabjoch,” known as the Tyrolean Iceman (or Ötzi). Ötzi was exposed in 1991 by the retreating glaciers, and his remains were radiocarbon-dated between 5.05 and 5.35 ka (39). The excellent preservation of his remains strongly suggests that he was buried quickly by snow and captured within the advancing glacier (39, 40).
These observations strongly suggest that the mid-Holocene transition from early to late Holocene conditions was abrupt and widespread, particularly in mid- to low latitudes, and it affected human activities over a wide geographical area.
So this is his explanation:
If these climate changes were abrupt responses to gradual changes in incoming solar radiation, then it would require forcing by nonlinear processes, possibly through vegetation and/or ocean temperature feedbacks (45).
Wow that's fascinating. So when we began entering the Ice Age again - the whole planet did a 180 in temperature shift through nonlinear amplification!!!
https://www.sciencedaily.com/releases/2004/12/041219142907.htm
Major Climate Change Occurred 5,200 Years Ago: Evidence Suggests That History Could Repeat Itself
- Date:
- December 24, 2004
- Source:
- Ohio State University
- Summary:
- Glaciologist Lonnie Thompson worries that he may have found clues that show history repeating itself, and if he is right, the result could have important implications to modern society. Thompson has spent his career trekking to the far corners of the world to find remote ice fields and then bring back cores drilled from their centers. Within those cores are the records of ancient climate from across the globe.
- Thompson believes that the 5,200-year old event may have been caused by a dramatic fluctuation in solar energy reaching the earth.
- Evidence shows that around 5,200 years ago, solar output first dropped precipitously and then surged over a short period. It is this huge solar energy oscillation that Thompson believes may have triggered the climate change he sees in all those records. “The climate system is remarkably sensitive to natural variability,” he said.
- https://www.britannica.com/explore/savingearth/climate-change-throughout-history
- The Dansgaard-Oeschger cycles of the last glacial period are now recognized as representing alternation between two climate states, with rapid transitions from one state to the other. A 200-year-long cooling event in the Northern Hemisphere approximately 8,200 years ago resulted from the rapid draining of glacial Lake Agassiz into the North Atlantic via the Great Lakes and St. Lawrence drainage. This event, characterized as a miniature version of the Younger Dryas, had ecological impacts in Europe and North America that included a rapid decline of hemlock populations in New England forests. In addition, evidence of another such transition, marked by a rapid drop in the water levels of lakes and bogs in eastern North America, occurred 5,200 years ago. It is recorded in ice cores from glaciers at high altitudes in tropical regions as well as tree-ring, lake-level, and peatland samples from temperate regions.
-
What happened to the sun over 7,000 years ago?
Analysis of tree rings reveals highly abnormal solar activity in the mid-Holocene
https://www.sciencedaily.com/releases/2017/02
/170207092720.htm
"The evidence is growing that climate in the post-ice age world is not as stable and is more variable than once thought," Dr. Bond said at an AGU session highlighting abrupt climate change during the Holocene era - the past 10,500 years after the last ice age ended and human civilization began to flourish. "The abrupt coolings in the Holocene are not as great as those that occurred during the ice ages, but still might be significant enough to cause severe winters, agricultural disruptions, and other adverse impacts on people."
The abrupt coolings occurred within 200 years, based on the layers of rock fragments that had been transported by glacial icebergs and sea ice to the North Atlantic, deposited on the seafloor and buried by subsequent sediments. At times of coolings, the amounts of rock fragments doubled or tripled in the ocean sediments. Also, different types of fragments suddenly appeared, indicating an increase in ice from several sources, including Iceland and perhaps Greenland, northern Canada and Svalbard, an island in the Arctic Ocean. The regularly spaced layers of ice-delivered debris showed that the amount of floating ice increased suddenly every 1,000 to 3,000 years. Dr. Bond dated the peaks of ice-delivered debris at about 12,300; 10,800; 8,000; 5,700; 3,900; 2,750 and 800 years ago.
http://www.columbia.edu/cu/pr/95/18779.html
Changes in the chemical composition of these ice cores reveal that the surrounding atmospheric temperature repeatedly warmed by 8-16℃, and each time within just a few decades.
https://theconversation.com/we-pieced-together-the-most-precise-records-of-major-climate-events-from-thousands-of-years-ago-heres-what-we-found-144575
However, long, high-quality stalagmite records are rare. Scientists from around the world have been working for more than 20 years to produce these records. Only now that enough records are available, we are able to make precise comparisons of the timing of Dansgaard-Oeschger events between different regions.
We collated and compared 63 published stalagmite records from caves in Asia, Europe and South America, and we determined the timings of abrupt climate changes in each.
http://www-leland.stanford.edu/~meehan/donnelly/paleolt.html
Some tentative conclusions: Millennial-scale warming terminates with a period of climatic disturbance (so-called "Piora oscillation") and flooding in the lower latitudes (Nile, Arizona, Morocco, Israel, Mesopotamia), followed by a drought; general, worldwide, climate-driven shock to early societies living in "edenic" geography of plenty with "fertile crescent" survivors organizing into more centrally directed and hierarchical culture based on irrigation. Abrupt cooling at higher latitudes, possibly related to oceanic effects, especially in Northern Europe, corresponding to peak of megalith cultures. Probable oscillation in sea level at 3200 BC followed by 10-15 ft. alluvial deposition in river valleys.
https://en.wikipedia.org/wiki/Piora_Oscillation
A few commentators have associated the climate changes of this period with the end of the Uruk period, as a Dark Age associated with the floods of the Gilgamesh epic and Noah's flood of the Book of Genesis.[2]
The cause or causes of the Piora Oscillation are debated. A Greenland ice core, GISP2, shows a sulfate spike and methane trough c. 3250 BCE, suggesting an unusual occurrence — either a volcanic eruption or a meteor or an asteroid impact event. Other authorities associate the Piora Oscillation with other comparable events, like the 8.2 kiloyear event, that recur in climate history, as part of a larger 1500-year climate cycle.
However, more recent work has shown that these tracers provide little support for 1,500-year intervals of climate change, and the reported c. 1,500 ± 500-year period was a statistical artifact.[2] Furthermore, following publication of the Greenland Ice Core Chronology 2005 (GICC05)[4] for the North GRIP ice core, it became clear that Dansgaard–Oeschger events also show no such pattern.[2][5][6
https://web.stanford.edu/~meehan/donnellyr/summary.html
. Paleoclimate data, primarily from Cyprus and the Levant, suggest that a 300-year period of arid conditions that began around 3200 yrs BP led to reductions in agricultural productivity and subsequently contributed to a general socioeconomic crisis in the eastern Mediterranean [10,14,15,18]. However, it was recently pointed out that many of these datasets do not have sufficient chronological resolution to reliably tie climate information to archaeological data [20]. Despite chronological uncertainties and the fact that attributing sociopolitical changes to drought can be seen as overly simplistic and deterministic [21,24,25], the idea of widespread aridity has recently gained a prominent position in discussions about LBA societal change in the eastern Mediterranean as well as on the Greek mainland. Even though direct climate evidence from mainland Greece has not been available for this period, it has been suggested that the destruction of the Mycenaean Palatial centers towards the end of the LBA should be viewed in light of the severe aridity recorded for this period elsewhere see e.g. [10]. In this paper, we present new high-resolution paleoclimate data extracted from a cave located just off the coast of the Greek mainland, in close proximity to one of the major Mycenaean Palatial centers.
Late Bronze Age climate change and the destruction of the Mycenaean Palace of Nestor at Pylos
For example, while surveying 250,000 years of climate history, historian John Brooke of Ohio State University argues in an ambitious new book that the onset of a “cold, dry climate has to be a fundamental explanation of the demise of the Bronze Age of the greater Mediterranean.” (Brooke, 2014) Harvests failed in a changing climate, and subsequent food shortages undermined palace economies while provoking mass migration. Civilizations clashed, populations mingled and therefore spread disease, and piracy spread across the Mediterranean. Other scholars have tied roughly synchronous collapse in Northwestern Europe to changing climatic conditions. (Raftery, 1994; Tipping et al., 2008)
It is a compelling story, especially because it appears to offer a vivid warning for us today. However, like many straightforward narratives that tie climate change to historical collapse, that story is being revised by cutting-edge, interdisciplinary scholarship. In a paper recently published in Proceedings of the National Academy of Sciences, a team of scientists under lead author Ian Armit of the University of Bradford set out to reconstruct the late Bronze Age climate with unprecedented precision.Armit and his coauthors conclude that, in an age of global warming, “it is easy to view climate as the primary driver of past cultural change,” but “such assumptions need to be critically assessed using high-precision chronologies” that “guard against misleading correlations.” Sometimes historical work could use a little more methodological rigour, and certainly scientists, archaeologists, and historians should be prepared to work together in uncovering the climate history of the distant past.
However, at other times excellent historical work is grounded on cutting-edge scientific data that is revised by later studies. That can undermine some compelling narratives, but that does mean those narratives were never worth telling. Scholarship is a conversation, and that conversation gains depth through daring, provocative stories.Rapid climate change did not cause population collapse at the end of the European Bronze Age
His book, Climate Change and the Course of Global History: A Rough Journey, published in the spring of 2014 by Cambridge University Press, examines the long material and natural history of the human condition.
https://open.spotify.com/episode/4PmVdjigsvyA9ZHe1QtilA
podcast interview
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