The cyclical nature of climate change
The curve of the population of France since Antiquity shows successive periods of growth followed by impressive falls. The first phenomenon is a fairly high growth until around the year 350. The French population doubled between -100 BC and 300 AD.
It then doubled between 800 and 1200 AD. It doubled again between 1500 and 1900. The falls, in both intervals, correspond to the great pandemics.
- The Roman period
The Roman era was a golden age. 60 years before Christ, Julius Caesar’s Rome had only one stone temple. At the beginning of Nero’s reign, the houses were still mainly made of wood and Rome suffered a terrible fire. It was rebuilt in stone and brick. Of course, all the temples and theatres were already made of stone. The city of Pompeii was made of stone and brick when Vesuvius erupted in 79 AD. This prosperous period seems to have been characterised by high temperature and high humidity. Pliny the Elder reports that olive trees were cultivated at unusual altitudes and latitudes.
The boom at the beginning of the Roman imperial era was most certainly due to climatic disruption. In contrast to cooling, which would be dramatic, warming increases agricultural productivity and therefore economic development. This favourable climatic episode was followed by an economic collapse.
Before the end of the second century, the terrible epidemic of the “Antonine plague” ravaged the West (How the Roman Empire collapsed, Kyle Harper, © La Découverte, 2019). Emperor Marcus Aurelius, warring in the east of the Roman Empire, was one of its first victims in 180. It was followed by two other epidemics in 249 and 541. The population collapsed. The Arab conquerors had no difficulty invading the Middle East and the depopulated Maghreb.
- The Middle Ages
However, the approach of the year 1000 shows an impressive revival of the population, a thousand years after that of the Roman period. If the growth of the Roman period begins to be linked to the climate, that of the year 1000 is undoubtedly the result of a remarkable rise in temperature.
Around the year 1000, the West was marked by unprecedented economic and demographic development. At that time, an extraordinary evolution of tools, armament and architecture was observed. Proof of this is given by the Bayeux Tapestry. In 1066, therefore, all the soldiers of William the Conqueror wear iron helmet, although it was earlier a privilege of high rank warriors as shown by their graves!
A favourable climate made it possible to cultivate areas as unwelcoming as the slopes of the summits of the Massif Central. They were subsequently abandoned and never exploited again. It seems that this warming was limited to the North Atlantic. This period marks the only colonisation of Greenland, literally “the green country”, which was never green again afterwards! The Vikings settled there in number from 986 onwards. However, when the climate change of the time came to an end, they began to disappear, as they could not withstand the normal climate of the region. Only the Inuit, originating from these regions, are able to live there sustainably, thanks to an adaptation of their organism. The last descendants of the Vikings had disappeared 450 years after they landed on the island.
At the beginning of the 14th century, waves of intense cold could be detected in the cores of the glacial zones. But the climatic warming had had to stop long before.
From 1347 onwards, this reversal of temperature led to a new epidemic, even more terrible than the previous ones: the “black plague”. The population of Europe fell back to the maximum level of the Roman era! It should be noted that these pandemics occurred during periods of cold weather and always began in the Mediterranean ports so coming from the Far East.
It would therefore be the plague bacillus, which is active in winter. Evidence from the period allows us to identify the “Black Plague” of 1347 and the “Justinian Plague” of 541 with the bubonic plague. The swelling of the lymph nodes, which is 80% fatal, is characteristic. However, this symptom does not always exist, particularly in the case of previous epidemics which could result from the same bacillus before the final mutation of amino acid 259 of the bacillus yersinia pestis.
The fact is that the famous ratus ratus invaded the West, to the furthest point in Scotland, almost 1000 years BC. This black rat is the main vehicle for the bacillus, which it transmits to fleas, which spread the disease.
- The Present Era
Today we are living through a similar climatic episode. No one doubts it any more. The global warming would result from the methane released by cows and the carbon dioxide emitted by our thermal power stations and cars.
In my childhood, during meals, I used to hear my parents worried about the inexorable cooling of the Planet. It was mentioned in all the newspapers. They described other planets with freezing temperatures. I was terrified. Our Brittany spaniel, who was scratching at the window to get in, seemed to want to take advantage of the warmth of the house before being turned into a block of ice!
A few years ago, an artificial satellite observed a significant layer of methane above the Aigle forest, near Compiègne in the Oise department. This was after a long period without wind. Where does methane come from? From rotting leaves, branches, tree trunks and roots. Almost as much methane. Moreover, the forests are strewn with glaucous puddles from which methane vapours bubble out.
The mass of a beautiful 20-year-old tree, taking into account the mass of the leaves produced each year, is measured in tonnes; the total mass of hay consumed in 20 years by a cow is measured in tens of tonnes, but tonnes of dry matter must be removed from the milk. Milk gives little methane. The equivalence of one tree, one cow would certainly be very exaggerated, but there are three thousand billion trees on Earth. The unfortunate cows are only one and a half billion.
While the open-air fermentation of dead leaves and branches produces carbon dioxide, those underneath, or in the water, are deprived of oxygen. They are methanised and thus give the forests a positive oxygen balance. The “angel’s share”, to use the image of the cognac cellar masters, is the share of the alcohol that evaporates from the barrels. Without a share of methanisation of leaves, dead branches, roots and abandoned trunks, the oxygen balance of the forests would be neutral as long as the forest park is stable.
- Antiquity
The three occurrences of the Roman period, the year 1000 and the present period lead us to attribute a periodicity of about a thousand years to climatic disturbances. It is therefore necessary to try to go back in time. Of course, we find the Flood in the Bible, but Plato, in The Laws (III, 677a) and in the Timaeus (24-25b), mentions cyclical dramas that would have periodically brought mankind back to the deepest destitution. There is talk of floods, plague epidemics and many other scourges that would have practically destroyed mankind. The last mentioned occurrence, however, would be a distant memory. The colds that cause plague epidemics occur about 200 years after warming. According to the work of ethnologists on the oral transmission of traditions, the memory may well have lasted for three or four hundred years. Plato therefore referred to an epidemic that probably occurred 750 BC, following a warming that would have marked the beginning of the first millennium BC
- Prehistoric times
A funerary boat was discovered in 2012 a few kilometres from Giza in a mastaba of the First Dynasty and thus dating from 3150 to 2900 BC. The construction of the Mastabas characterises an advanced civilisation with a large workforce.
On the other hand, the imposing pyramid of Cheops would have been built only around 2560 BC. The cedar that was used to build it, the boat found nearby, is said to have been built much earlier according to the carbon 14 measurement. This is the date of the formation of the wood. Once the wood is formed, it retains the percentage of carbon 14 in the atmosphere at that time. This cedar could be about a hundred years old, which allows us to date the boat from the same period as the pyramid.
Stonehenge in the UK was built at the same time as the Great Pyramids, around 3000 BC, but this is a very approximate dating based on signs related to the use of the site rather than its construction.
The climatic event of “4200 BP”, a terrible period of drought, dates from 2200 BC, it accompanied an intense cooling, traces of which are still visible in glaciers all over the world. This episode can be thought to be part of the intermediate period between the warming of 3000 BC and that of 2000 BC.
On the other hand, unlike the warming of 3000 BC, the cyclical episode of 2000 BC left no obvious traces. Except for the remarkable development of Babylon from the beginning of the second millennium.
The great Mycenaean civilisation began around 1600 BC. Four hundred years later, around 1200, all the Mycenaean palaces and temples were already in ruins. The rich valleys of Laconia and Attica were deserted.
But prosperity returned around the year 1000 B.C.. The temple of Solomon in Jerusalem, an imposing edifice, dates from this period. The year 1000 B.C. also marks, on the other side of the continent, the emergence of a new dynasty in China, the Zhou.
Cooling, which provoked, in particular, plague epidemics, occurred between the warming periods. After 800, therefore after Homer, all Greece was devastated and was completely depopulated before two successive invasions from the north. Plato could have grouped these disasters together.
It can also be pointed out that the end of the Roman Republic a little more than a century before the beginning of our era was marked by a general impoverishment and the abandonment of cultures throughout Italy. A very troubled period that can be traced back to the disasters that took place before the end of the first millennium BC.
The mummy of Ötzi, found on the border between Italy and Austria in 1991, lived around 3300-3250 BC. The temperature must certainly have been higher then it was until its discovery. The mummy has remained frozen without interruption until the present day, otherwise it would have rotted. Even the disturbance in the year 1000 was not enough. And we are still a long way from that: the valleys of Greenland are not yet green! Nostalgic novels will wait. The mummy has probably benefited, if I dare say so, from a local treatment. The drop in the level of the Alpine glaciers began to accelerate as early as the 1970s, long before there was any talk of global warming.
Conclusion
All this leads to a cyclical phenomenon and therefore related to astronomy, in particular to gravitation, which is probably not exclusively mathematical and invariant. The periodicity would be about a thousand years. The current abnormal displacement of the Earth’s magnetic pole could also be related to this phenomenon.
Depressions seem to move more slowly and irregularly than before. Such changes have been observed in the Middle East. It must be said that the circulation of depressions remains very mysterious, especially in the light of the El Niño phenomenon. Scientists claim that these changes in the circulation of depressions are the result of global warming resulting from human activities. I say the exact opposite. These changes are the cause of the current climate change, just as they have been the cause of previous climate changes. The atmospheric pollution that marks our time did not exist in previous episodes.
Even if the current climate change is in no way the result of human activity, the fact remains that industrial development has been polluting the atmosphere for more than two centuries. In the West, things have changed. I sometimes re-read the Yellow Mark, the most famous cartoons of Edgar Jacobs’ “Blake and Mortimer”. London was bathed in its famous smog, a thick fog caused by the fumes from coal-fired heating. But I go to London from time to time, in all seasons. Sometimes there is fog, a light fog. Today there is smog in India and China.
Whatever the cause of climate change, we cannot continue to pollute the atmosphere and the oceans. If we link climate change to a cause, even a probable one, we risk turning away from the fight against pollution if that cause appears to be wrong.
The risk is the same when you mix all the problems together. Fine particles, which I have just mentioned with the “Yellow Mark” smog, are a health risk. The fine particles cause a “climate cooling” (DOI: 10.1126/science.aat1723).
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Doug Harrison
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I have not heard of this author. It would have been nice to have seen his bio at the end as is usually done here.
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Jerry Krause
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Hi Doug,
Do you really consider what Jean wrote needs a bio to validate what was written?
Have a good day, Jerry
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Koen Vogel
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Hi Jean,
Thanks for this great summary. I had seen most of the historical evidence of previous warming and cooling periods in other publications, but it still would be nice to get some external references in the text. I do not see how gravitation could create 1000 year climate cycles, so perhaps you can expand on that in a future article. I have a PROM article up that links these centennial-scale climate cycles to solar cycles, via the Earth’s geomagnetic field (https://principia-scientific.com/wp-content/uploads/2020/07/vogel-prom-paper.pdf). Our current cycle’s magnetic/climate minimum was experienced around 1600 (Little Ice Age/Maunder Minimum) which (assuming 1000 year cycles) fits well with a climate maximum around 1100, but indicates we still have 80 years to go before peaking again. I don’t think these cycles are that precise though, and wouldn’t be surprised if we have already peaked in 2020 or will peak within the next few years.
It’s good to keep repeating the evidence that the current warming is mainly a North Atlantic event, and that human’s have witnessed several such cycles according to the written record.
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Jerry Krause
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Hi Koen,
When you wrote: “I do not see how gravitation could create 1000 year climate cycles, so perhaps you can expand on that in a future article.”, do you might be asking Jean to do the impossible.
Newton clearly wrote (as translated by Motte): “But hitherto I have not been able to discover the cause of those properties of gravity from phenomena, and I frame no hypotheses.”‘
And Richard Feynman wrote (“What Do You Care What Other People Think?”) what his father told him about observations he had brought to him for explanation. ” “That, nobody knows,” he said. “The general principle is that things which are moving tend to keep on moving, and things which are standing still tend to stand still, unless you push them hard. The tendency is called ‘inertia,’ but nobody knows why it’s true.” ”
Now, I do not claim that it is not possible to explain about what you asked Jean, But I do question if he or you have any actual detailed observations of the factors which caused glaciers (for which there is unquestionable evidence) which covered the northern portions of the northern hemisphere continents beyond 45 degrees north in some cases little more than 10,000 years ago. And I read that the geologist, John P. Bluemle, who had spend his entire professional career actually study the evidence of “North Dakota’s Geologic Legacy’ has observed evidence there were previous glaciations in the past before the most recent. And I have not yet read that anyone claims to explain the factors involved in how it is that the most recent glaciation occurred. Maybe they have for I do not claim to have read everything that has been written.
But I know some very fundamental observations cannot be explanation. All we know is what happens and not necessarily how it happens. And I know that Bluemle spent his lifetime merely looking the evidence of what happened. Which is where a scientific study should begin.
Have a good day, Jerry
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Koen Vogel
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Hi Jerry,
You are a font of references; I am continually learning. My question pertained more to the observed 1000 year cycle observed in the article. I have never heard of a 1000 year gravitational cycle, so I was inquiring. I do see a strong link between this 1000 year cycle and the multi-centennial solar cycle (Maunder minimum to present) and I can demonstrate it links to the Earth’s multi-centennial geomagnetic cycle, which in turn can be linked to climate change. I’ll get a news article out. Going back further, to the last ice age, is more speculative, but I would suspect a geomagnetic link there, too. There is strong evidence that Northeastern Siberia had a relatively benign climate then, with large herds of mammoths surviving on the plains, at the same time that Canada was covered in ice. If the North Magnetic Pole was near Northern Siberia (it seems to be headed there now), then this would cause relatively cooler conditions in the North Atlantic, and warmer conditions in Siberia. But that’s still very speculative.
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Jerry Krause
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Hi Koen,
I have a poor memory and I just discovered we had an extended conversation in August. So I going back there to refresh my memory. So, stay tuned and I will be back.
Have a good day, Jerry
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Jerry Krause
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Hi Koen,
First, I am having trouble connecting with PSI the previous conventional way. Then I have just had problems connecting with your August 17 (?) posting. But finally did. I have tried to find your Prom article without any success. But I did read your bio at the end of your Aug posting. And I would very much like to have a private conversation with you where our conversation would not be terminated by no more comments.
The prime reason for a private conversation is to eliminate the distraction of the other comments of others which you needed to address.
I see I referred to the fresh snow and melted water puddles about which I consider you did not address. I do not believe that the pressure ridges and leads are individually being being observed from a satellite. The satellite ‘image’ must be an average of an actually very variable surface.
I have full confidence in your ability to understand my ‘observations which you maybe have overllooked just as it seems that you dismissed the great variability of winter temperatures from one year to the next in the figure who brought to the attention of PSE readers.
Galileo’s used brief comments being made by 3 different people (points of view) to communicate that he had ‘learned’ via his creative and clever simple experiments. I have to ask you: Have you read Crew’s and de Salvio’s English translation of his book.
I consider it is always wise to begin at the beginning.
Have a good day, Jerry
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Jerry Krause
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Hi Koen,
Just checked about the 11 year solar cycle which I had already forgotten that I knew a little about. But before I had not seen the conflict between this 11 year cycle and that during the ice age that the sun was seen to be ‘quiet’ for more than a century and I read there was no aurora phenomenon during this long period. So we know, without much question, that there is this relationship between the sun’s sun-spot activity and the ‘winter’ temperatures which might have some influence upon the summer’s temperatures. But I haven’t read much about the summer’s temperatures during the Northern hemisphere’s summer. And I do not remember reading about the Southern Hemisphere’s winter temperatures.
So despite my lack of information foolishly consider I can offer a viable explanation how the sun’s activity can influence the earth’s weather. Which average of weather is climate.
And I will ramble a bit and state it, my foolish (because I lack much information which must exist somewhere) explanation, involves the stratosphere.
Have a good day, Jerry
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T. C. Clark
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The climate cycles over the last 10,000 years are measured in centuries…it is not precise clockwork like the orbital mechanics of the earth. It is roughly warming for about 2 to 3 centuries followed by cooling for 2 or 3 centuries. There was the Little Ice Age….the Medieval Warming Period….the Dark Ages Cooling Period….the Roman Warming Period…and today we have the Modern Warming Period which should end this century. In 1609, the Jamestown Virginia settlement was suffering from the cold – the James River almost froze completely over……a thousand years ago the Vikings settled southern Greenland because it was warm enough for trees to grow there. The cycles are not fully understood….the sun cycles and earth’s orbit variations appear to contribute to the cycles. Grand Solar Minimum….keep cool….cooler temps ahead…..regardless of CO2.
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