By Andy May
I last wrote about Climate Change and Civilization in the Last 4,000 Years in 2016. Since then, a lot has changed, and I’ve learned a lot more about the subject. First, we learned that various air and ocean temperature proxies, such as δ18O ice cores or tree rings, are all different. For a discussion of some of the temperature proxies in use and the problems with them, see here. Proxies have different accuracies, are often sensitive to different seasonal temperatures, and have different temporal resolutions. Thus, as Soon and Baliunas pointed out in 2003, everything is local and “cannot be combined into a hemispheric or global quantitative composite.”
The global average surface temperature (GAST) reconstruction relied on in the IPCC AR6 report is by Kaufman, et al. The authors admit that the average distance between each temperature (temporal resolution) is 164 years. So, to properly compare all global instrumental temperature records to proxies, one must average all daily readings since 1860 into a single point. That is, the rate of warming since 1860 is irrelevant, the proxy record cannot see a 164-year increase. The issue of comparing modern daily instrumental temperature records with proxies is discussed by Renee Hannon here.
Most temperature proxies are sensitive to only one season, but it is clear that seasonal temperatures vary to a different extent and that annual average temperatures vary more than seasonal temperatures. Statistically mixing to create an accurate GAST record of the distant past is not possible. This issue is discussed in more detail here and here. More proxies are affected by frequency of precipitation and/or CO2 level as well as temperature. We know CO2 it is higher now than it was a few thousand years ago and cannot correct the frequency or amount of rain.
While combining hundreds of proxies into one composite “global” or “hemispheric” record is a fool’s errand, we can look at high-resolution, high-quality local proxies from many places to get a qualitative sense of global or hemispheric climate change, which as well as done by Soon and Baliunas in 2003. Two records are particularly helpful, the Greenland ice core record by Vinther, et al. and Indonesia Throughflow water depth record of 500 meters from Makassar Strait by Rosenthal, et al. The Makassar Strait record is representative of the north Pacific sea surface temperature and the Vinther Greenland record is representative of air temperature in the Greenland-Renland-Agassiz region. The Vinther record is superior to the more commonly used GISP2 record (Alley, 2004) & (Alley, 2000) because it records elevation changes and ice flow. Both impair GISP2 reconstruction.
The temperature records of Vinther and Rosenthal have a resolution of 20 years over a period of 4,000 years, which is a good resolution for a proxy. The accuracy is good in both records and about ± 0.3 ° C. Both are Northern Hemisphere proxies but are 9,500 miles apart. They are compared with the same Antarctic proxy (10 years resolution) (Jouzel, et al., 2007) in figure 1. As you can see, the average Northern Hemisphere proxy with the Southern Hemisphere proxy is not always good, the temperature trends are different. with latitude.
As figure 1 suggests the long temperature drop labeled “Neoglacial” is primarily a Northern Hemisphere phenomenon, this is more clearly seen in figure 1 here. Figure 2 compares Vinther and Rosenthal records from figure 1 with selected historical events and Usoskin’s grand minima (SGM) records (Usoskin, 2017) shown as black dots outlined in orange. Notice the smoothed version of the Vinther record is plotted in figure 1 and the unsmoothed 20-year record is plotted in figure 2. To see figure 2 in full resolution, click on the image or here. The image prints well on 8.5 × 11 inch or A4 paper.
The Blytt-Sernander climate period (Schrøder, et al., 2004) is identified at the top of figure 2. Below the Vinther and Rosenthal proxy temperature records are plotted along with major historical events. The red dashed line on the right is a smooth HadCRUT4 concatenation of six populated grid cells (mean grid cells with temperature values) near Greenland that have sufficient data since 1850. The lines are vertically aligned to the Vinther record where they overlap. Vinther’s and HadCRUT4’s 20-year smooth record shows a peak near 1934. Rosenthal’s record from 500 meters down the Makassar Strait in Indonesia. The red box is the average temperature, at the same depth, from 2004-2016, from the global ocean climatology database of the University of Hamburg (Gouretski, 2019).
Major historical climatic periods are identified below the solar grand minima. Both proxies show a decrease in Northern Hemisphere temperatures between 1700 and 1810. Combined, they show peaks from 800 to 1000AD (Medieval Warm Period), 500BC to 400AD (Roman Warm Period), and 1700BC to 1000BC (Minoan Warm Period) . ). Significant differences in proxies are seen from 1400 to 800BC, 200BC to 0AD, and 300 to 500AD.
In 2000 BC, the world’s most advanced cultures were in the eastern Mediterranean and they were in trouble. The Old Kingdom of Egypt had fallen and was in the Dark Ages of Egypt, before the Akkadian Empire (mostly in present-day Iraq) had fallen. What grew out of the chaos was the New Kingdom of Egypt in 1975BC and the development of the great Minoan “Palaces” on Crete and the surrounding islands. The Minoans had the most advanced ships of the time and traded extensively. Minoan trading culture was at its peak between 1690BC and 1450BC when an unknown disaster destroyed all the palaces except Knossos in Crete (Cunliffe, 2008, p. 190). Knossos survived until the Mycenaean and Hittite civilizations collapsed in the great cataclysm of 1177BC (Cline, 2014).
To the east, there was an advanced civilization in northwestern India and Pakistan called Harappa. While the Harappan civilization can trace its roots to 5500BC or earlier, the mature Harappan period was between 2600BC and 1300BC when it collapsed. Although the civilizations of Mesopotamia and Egypt predated the Harappan period, they were probably greater than (Britannica).
In China, the Shang Dynasty ruled most of the Yellow River valley from 1600 BC until about 1046 BC (Britannica) when it collapsed and was overthrown by King Wu of Zhou. The last decade of the Shang Dynasty was a very turbulent and cold and dry climate, with dust storms common. Ice appeared on the Yellow River and there were frequent crop failures and famines. Bad weather helped King Wu’s conquest (Behringer, 2010, p. 57).
In 800BC there was a “Climate Plunge,” sometimes called the Hallstatt disaster, in Europe and the Middle East (Behringer, 2010, p. 60). This marks the beginning of the Iron Age in Europe and is associated with a drop in temperature, longer winters, and the advance of glaciers. Massive migrations took place, and civil war broke out in Egypt.
China was finally unified by Ch’in around 200BC, but chaos ensued after his death and the Han Dynasty was formed in 202BC. It lasted until 220AD. This was also the time when the Roman Empire was at its peak (Behringer, 2010, p. 62).
Wine was introduced to England by the Roman Emperor Probus in 280 AD. The worsening climate started a period of “great migration” around 250AD, causing problems in the Roman Empire and the fall of the Han Dynasty in 220AD. Later, around 375 the Huns invaded Europe, driving the Germans to Rome, which they destroyed. Rome had a brief rise around 400AD, but eventually fell. A climatic disaster around 537 AD, possibly due to a large tropical volcanic eruption, helped bring about the collapse of the Empire. This was near the beginning of the European Dark Ages.
One of the worst climate disasters in recorded history occurred around 800 AD. In 843, a hungry wolf burst into a church in Sénonais, France during a service and attacked the sheep. Charlemagne deployed teams of wolf hunters in every county in his kingdom. A third of people in Europe died in 784AD. The decade around 800AD was miserable in Europe. But that time did not exist in China and Japan. However, the Maya suffered several severe droughts between 760 and 910AD and the Maya government and nobility disappeared around 900AD amid a severe population decline (Behringer, 2010, p. 71).
Around the mid-800s the Vikings appeared as the North Atlantic warmed and conquered parts of England, Ireland, Russia, France, and Sicily. The Medieval Warm Period began earlier in Northern Europe than in the South, which benefited from the Vikings. They settled in Greenland in 985AD and they prospered until around 1410 when the last letter from Greenland arrived at the Vatican. After 1410 they all died and some of their farms are now in permafrost. Ships attempting to sail to Greenland during this time could not pass through the massive icebergs.
While most sources place the Little Ice Age around the 1300s, it didn’t begin in earnest until the late 1400s. The most severe part of the Little Ice Age was from 1645 to 1715, although very cold periods occurred from 1310 to 1322, 1560-1600, and 1800-1850. The period from 1560-1660 became known as the “age of witch persecutions” (Behringer, 2010, p. 130). There must be someone or some group to blame for the bad weather, and the group most often blamed is older single women. Others claim the weather is God’s punishment for sins such as sodomy or fornication.
The effects on society of the poor weather of the Little Ice Age were terrible. The mid-1600s saw more wars worldwide than any other era until the 1940s (Parker, 2008). In the 1640s, the Ming Dynasty and the Polish-Lithuanian Commonwealth collapsed. Serious revolts shook England, Spain, Russia, France, and Istanbul. In London, King Charles I became the first monarch to be tried. One of the next Chinese emperors, Yongzheng, estimated that at this time more than half of the Chinese population died (Parker, 2008).
In France the Fronde Rebellion (1648-1653) and the resulting disease, want, and suffering killed two-thirds of the population of the villages around Paris. Thomas Hobbs wrote in 1651 that “human life is solitary, poor, bad, rough, and short” (Parker, 2008).
It was not only the cold that made the Little Ice Age miserable, but also droughts, high winds, and extremely hot summers (Mei & Crok, 2024). The weather in the Little Ice Age was more extreme than it is today. I have written elsewhere that storms were worse during the Little Ice Age see figure 6 here. This is logical because colder periods have a steeper temperature gradient from the tropics to the poles and that gradient favors storms.
As Geoffrey Parker writes, the extraordinary claims of the suffering of people who lived in the 1600s have been shown to be true. It is understandable that many people who remember this time are skeptical of the story, but it has been shown to be true time and time again. The Little Ice Age is real, and it is destroying humanity.
Many paleoclimatologists, archaeologists, and historians agree that there is a correspondence between the level of solar activity and climate. They also agree that humans do better in warmer weather than in colder weather. Time for a “consensus” to face historical and archaeological facts.
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