Since the beginning of this year, from the heavy rain in Zhengzhou to the flood and high temperature in Europe, extreme weather has appeared frequently. Mankind has experienced the industrial revolution, the electronic information revolution, and to today's new technological revolution, has made progress, but paid a heavy price at the expense of the environment, and climate deterioration is not only a global problem, but also a historical problem. Mr. Zhu Kezhen has sorted out and studied the basic laws of China's climate change over the past 5,000 years, and divided China's climate change into archaeological period, phenological period, Fangzhi period and instrument measurement period. Mr. Zhu believes that the temperature in China during the Yangshao Yin Ruins period was relatively mild. Since the Western Zhou Dynasty, climate changes have become more frequent. During the Western Zhou Dynasty, the temperature in China went from warm to cold. From the spring and autumn to the Qin and Han Dynasties, the temperature gradually became milder. During the Southern and Northern Dynasties of the Wei and Jin Dynasties, it was once again plunged into a period of low temperature. The Sui and Tang dynasties went hand in hand with the warmth of the climate, and during the Song and Yuan dynasties, the temperature remained low again. By the Ming and Qing dynasties, that is, the so-called Fang Zhi period of Mr. Zhu, the climate was arranged in groups of warm and cold, and the changes tended to be stable. Overall, climate change and historical upheaval become a way to mutually corroborate each other. The change of climate and the regular cycle have become an important dimension for understanding the rise and fall of 5,000 years of history.
In addition, he found that any of the coldest periods seemed to start from the East Asian and Pacific coasts, and the cold fluctuations spread westward to the Atlantic coasts of Europe and Africa, and also had a north-to-south trend. Climate fluctuations are worldwide, and although the coldest and warmest years in different regions occur in different years, they echo each other. For example, the temperature rise and fall in China in 5,000 years is roughly the same as the snow line in Norway, but there is a difference in the order. Greenland, on the other hand, is more than 20,000 kilometers away from China, but the ancient climate changes are the same, which is enough to show that this change is global.
Zhu Kezhen,200,000 old and strong (source network)
Zhu Kezhen (1890.3.7 – 1974.2.7), courtesy name Lotus, was a native of Dongguan Town, Shaoxing County, Zhejiang Province (now part of Shangyu District, Shaoxing City, Zhejiang Province). Academician of the Chinese Academy of Sciences, member of the Communist Party of China, meteorologist, geographer and educator of modern China. The founder of modern Chinese geography and meteorology.
Source network
A Preliminary Study of Climate Change in China in the Past 5,000 Years
Text | Zhu Kezhen, Journal of Archaeology, No. 1, 1972
The world climate in historical times has changed. The very rich Chinese historical documents have created extremely favorable conditions for studying China's ancient climate. Based on historical and archaeological excavation materials, the author proves that in the past five thousand years, the first two thousand years, that is, from the Yangshao culture era to the Yin Ruins era in Anyang, Henan, the average annual temperature was about 2 °C higher than now. After this, the average annual temperature oscillated from 2 to 3 °C, and the cold period occurred in the 1st millennium BC (the beginning of the Late Yin Dynasty), the 400th year (the Sixth Dynasty), the 1200th year AD (Southern Song Dynasty) and the 1700th year AD (late Ming and early Qing Dynasties). The Han and Tang dynasties were relatively warm eras. This climate change is worldwide. When the climate cools, it starts from the west coast of the Pacific Ocean and gradually moves west from Japan and eastern China to Western Europe. When the temperature rises, it travels from west to east. Fully understanding the historical climate change and grasping its laws, "ancient for the present", long-term forecasting of climate is complementary.
Ancient Chinese philosophers and writers such as Shen Kuo (1030-1094) and Liu Xianting (1648-1695) had long doubts about the climate impermanence of China's historical period, but they could not come up with many substantive facts to support it, so later generations did not pay much attention. Until the twenties of the present century, after the "May Fourth" Movement, that is, the anti-imperialist and anti-feudal movement, China began to produce a new revolutionary spirit, part of the advanced elements introduced Marxism-Leninism, established the Communist Party of China, and led the Chinese people to carry out new revolutionary struggles In this new situation, modern science was also promoted and expanded, such as the application of scientific methods for archaeological excavations, and the study of ancient history, geography, meteorology, etc. according to the excavation materials. Some people infer from this that three thousand years ago, the Yellow River Basin was as warm and humid as the Yangtze River Basin today. However, under the reactionary rule of the Kuomintang, after all, the achievements are limited or due to insufficient materials and make a wrong judgment For example, in the past three thousand years, China's climate has undergone many changes, but it is much slower than the changes in human history and society, some people do not understand this, and exaggerate the magnitude and importance of climate change based on fragmentary materials, which is not right At that time, the author also studied China's climate change according to the change of rainfall, because the change of rainfall is often affected by geography, so it is difficult to get the correct results.
Historical temperature changes (source network)
It was only under the leadership of the Communist Party of China that after the founding of the People's Republic of China in 1949, many factories, people's communes and research institutions were established, creating a broad realm for scientific research. More importantly, we have the theoretical guidance of Marxism-Leninism and Mao Zedong Thought, which have lifted the shackles on the authoritative ideas of Western bourgeois scientists, and China's scientific undertakings have developed vigorously.
Chairman Mao taught us: "Within the scope of the struggle for production and scientific experiments, human beings are always constantly evolving, and the natural world is always constantly developing, never stopping at one level. The argument of cessation, the argument of pessimism, the argument of inaction and complacency, are all wrong. Therefore, it is wrong, because these arguments are inconsistent with the historical facts of the development of human society over the past million years, nor with the historical facts of nature as we know so far, such as the history of the celestial body, the history of the earth, the history of biology, and the history of various other natural sciences. ”
In October 1958, Chairman Mao Zedong attended the Exhibition of Scientific and Technological Achievements of the Chinese Academy of Sciences, with Zhu Kezhen on the left, Guo Moruo on the left, and Hu Qiaomu on the right
At the beginning of the twentieth century, the Austrian professor J. Hann believes that the idealistic assertion that there was no change in the world climate in the period of human history has been rejected by the historical record of our country, as can be seen from the following discussion.
In the world, the discipline of paleoclimatology does not seem to have attracted the attention of geophysical scientists until the 1960s. In the sixties, three world conferences on paleoclimatology were held. Most of the articles presented at these conferences are about the climate of the geological epoch, and only a few discuss the climate of the historical epoch, which is undoubtedly due to the lack of reliable records of astronomical, meteorological and geophysical phenomena in the western and eastern countries of the historical period.
In this regard, only my country has the richest material. In many ancient documents in China, there are records of a series of natural disasters such as typhoons, floods, droughts, and freezes, as well as records of unusual phenomena such as sunspots, auroras, and comets. In 1955, the Astronomical Journal published an article entitled "New Table of Paleocolastic Stars", which included 90 new stars before the eighteenth century. After this article was published, it was highly valued by astronomers around the world. In 1956, the Chinese Academy of Sciences published a two-volume Chronology of Earthquake Data in China, including 1,180 earthquakes between the twelfth century BC and 1955 BC. In addition to providing indispensable reference materials for China's socialist construction, Chinese and foreign seismologists have welcomed these two books very much.
In China's historical documents, there are rich records of meteorology and phenology in the past, in addition to the official historical records of the past, the geographical records of many regions, as well as personal diaries and travel reports are recorded, but unfortunately this paper is very scattered, can only be a preliminary analysis of the material at hand, hoping to write a simple and concise outline of the main trends of climate change in the past five thousand years.
According to the nature of the material at hand, the time of nearly five thousand years can be divided into four periods:
The archaeological period, circa 3000-1100 BC, was not recorded in writing at that time (with the exception of the oracle bones).
2. The phenological period, from 1100 BC to 1400 AD, when there were written records of phenology, but there was no detailed regional report.
Third, the Fang Zhi period, from 1400 AD to 1900 AD, in most of China, there are locally written Fang Zhi and modified from time to time.
Fourth, during the period of instrument observation, China has had meteorological records of instrumental observation since 1900, but it is limited to the eastern coastal area.
The change of climate factors is extremely complex, and it is necessary to select a factor as an indicator, such as rainfall as an important factor in climate, but it is not suitable for measuring climate change. The reason is that in the East Asian monsoon region, the change of rainfall is often extreme, either drought or flood, and then the rainfall of the two neighboring places can be very different, on the contrary, the temperature change is small, although the difference of one degree Celsius, can also be precisely measured, in the winter and spring can affect the growth of crops. Moreover, the winter temperature is controlled by the high pressure of Siberia in the north, so that the temperature rise and fall in the eastern coastal area of China is relatively uniform, so this paper takes the rise and fall of winter temperature as the only indicator of Climate Change in China.
Map of 5,000-year historical temperature changes in China
<h1 class="pgc-h-arrow-right" data-track="340" > archaeological period (3000 BC - 1100 BC).</h1>
In the more than two decades since liberation, our archaeologists have carried out extensive excavations in different parts of our country. Banpo Village near Xi'an is one of the most well-known sites. According to a report published in 1963, between the autumn of 1954 and the summer of 1957, the Institute of Archaeology of the Chinese Academy of Sciences carried out excavations on this site for five seasons, excavating an area of about 10,000 square meters, discovering more than 40 house ruins, more than 200 storage cellars, about 250 tombs, and nearly 10,000 pieces of various artificial artifacts. According to research, agriculture clearly plays a major role in the lives of the people of Banpo. Millet is grown in crops, possibly some vegetables, and although pigs and dogs are also raised, hunting and fishing is still important. Remains of animal bones indicate that among the captured beasts the dove (aka the hydropotes inermis) and the bamboo rat (Rhizomys sinensis)...). The book argues that the site belonged to the Yangshao culture (isotope 5600-6080 years ago); and assumes that because the water musk and bamboo rat are subtropical animals, and such animals no longer exist in the Xi'an area, it is inferred that the climate at that time must have been warmer and wetter than it is now.
In Anyang, north of the Yellow River in Henan Province, there is another well-known ancient site, Yin Ruins. It was the capital of the Yin Dynasty (c. 1400-1100 BC). There is an abundance of subfossil animals. Yang Zhongjian and P. Teilhar de chardin studied it, and the results were published in a report by the former Beijing Geological Survey. In addition to the abundance of water musk and bamboo rats found here, as seen at the Banpo site, there are also ornithoppers (Tapirus indicus Cnvier), buffalo and wild boar. This makes De rijin, although he is a self-proclaimed conservative author of the issue of climate change in historical times, also admit that there is some minor climate change. Because many animals are now only found in the tropics and subtropics.
However, the more direct evidence for the climate change comes from the oracle bones of the Yin Dynasty with many rain inscriptions. More than twenty years ago, Hu Houxuan studied these oracle bones and discovered the following fact: during the Yin Dynasty, although Chinese used the lunar calendar, it was already known to add a leap month (called the thirteenth month) to maintain the correct season; thus the first month of the year was the first month of January or the first half of February in the current solar calendar. More than 100,000 oracle bones were found in Yin Ruins, thousands of which were related to the search for rain or snow. Of the oracle bones that can be dated, 137 are for rain and snow, and 14 are for rain. These accounts are scattered throughout the year, but most frequently in the first five months of the year, when there is a great need for rain and snow. Snowfall is rare during this time. At that time, the Anyang people planted rice and began planting in the second or third month, that is, in March of the solar calendar; it was about a month earlier than the current Anyang planting in mid-April. The thesis also states that in the time of Wuding (1324 BC?) A year 1365? An inscription on one of the oracle bones says that an elephant was acquired while hunting. This indicates that the sub-fossil elephants found in Yin Ruins must be indigenous, not as advocated by De Rijin, who believes that they were all imported from the south. Henan Province was originally called Yuzhou, and the word "Yu" is a sign that a person has led an elephant. This has implications.
Climate change in a place must affect plant species and animal species, but the plant structure is relatively fragile, so it is more difficult to preserve; but on the other hand, plants are not like animals can move, so it is more effective as a sign of climate change or more effective than animal fossils. For the half-slope formation, spore pollen analysis has been carried out, because there are not many pollen and spores, so for the temperature and cold situation at that time, there can be no positive results, and it can only be inferred that there was no big difference between that time and now, and the climate was semi-dry. From 1930 to 1931, longshan cultural sites were excavated in two towns in Licheng County, Shandong Province (latitude 35 ° 25 ′ N, longitude 119 ° 25 ′ E). A charcoalized bamboo knot was found in a ash pit, and some pottery-shaped bamboo knots resembled bamboo knots (a carbonized bamboo knot was found in the Longshan ash pit, according to the transmission of Comrade Yin Da, who participated in the excavation of the site at that time. Some of the pottery vessels excavated from the Longshan culture resemble bamboo knots, which are reported to Comrade Xia Nai. ）。 This shows that in the late Neolithic period, the distribution of bamboo in the Yellow River Basin was up to the eastern coastal area.
From the above facts, we can assume that since the Yangshao culture 5,000 years ago, the northern limit of bamboo distribution has receded from 1 to 3° to the south. If you examine the average monthly temperature and annual average temperature in the lower reaches of the Yellow River and the lower reaches of the Yangtze River, it can be seen that the average temperature of the first month has decreased by 3 to 5 °C, and the average annual temperature has decreased by about 2 °C. Some historians believe that the Yellow River Basin was nearly tropical at that time, although it is too much to say, but in places like Anyang, the average monthly temperature dropped by 3 to 5 ° C, which must have made a big difference in the total amount of ice and snow in winter and made it easy for people to perceive. Those who believe that the climate after the Ice Age is unchanging violates the principle of dialectics; in fact, the climate change in the historical period is the same as the climate change in the geological period, but on a smaller scale. The average annual temperature of modern times is warmer than in the recent ice age, that is, about 10,000 or 20,000 years ago, and the average annual temperature in historical periods has changed by only two or three degrees at most. The climate has changed in the past, it is changing now, and it will change in the future. During the past five thousand years, it can be said that the Yangshao and Yinxu eras were China's mild climate era, when the Xi'an and Anyang regions were very rich in subtropical plant species and animal species. However, the details of climate change have yet to be confirmed by more discoveries.
<h1 class="pgc-h-arrow-right" data-track="338" > phenological period (1100-1400 BC).</h1>
Before the observation instrument, people should know that the cold and summer of the year come and go, just use the human eye to see frost and snow, rivers and rivers frozen, trees sprouting leaves, flowering and fruiting, migratory birds coming and going in spring and autumn, and so on, this is phenology. The working people of our country, because of their agricultural needs, pioneered this observation as early as the beginning of the Zhou Dynasty, that is, in the eleventh century BC. For example, "Xia Xiaozheng" and "Li Ji Yue Ling" all contain the results of previous phenological observations. Accumulated three thousand years of experience, the material is extremely rich, which is unattainable by any country in the world.
The establishment of the Zhou Dynasty (1066-249 BC) was located in Hojing near Xi'an, which came to the phenological period. At that time, official documents were first inscribed in bronze and then written in bamboo jane. Many of China's square characters, represented by oligurations, were formed at that time. From these words, it is conceivable that bamboo played a significant role in people's daily lives at that time. Names such as clothes, hats, utensils, books, furniture, sports materials, architectural parts, and musical instruments in the block characters all have the prefix "bamboo", indicating that these things were originally made of bamboo. Therefore, we can assume that a warm climate in the early Zhou Dynasty allowed bamboo to grow widely in the Yellow River Basin, but not now.
The mild climate can also be confirmed by the earliest phenological observations in China. Since the Neolithic period, all ethnic groups living in the Yellow River Basin at that time have been engaged in agriculture and animal husbandry. For them, the movement of the seasons is a top priority. The working people of that time had recognized two "equinox" points (the spring and autumn equinoxes) and two "to" points (the summer solstice and the winter solstice) of the year, but did not know how many days there were in a solar year. Therefore, there is a hurry to find a way to fix the spring equinox as the start date of agricultural operations. The people of Shang Zhou observed the second of the twenty-eight houses that appeared in the early spring and twilight, that is, the red mars to fix the spring equinox (Zuo Chuan, Xianggong 9th year" "The Marquis of Jin asked Yu Shi weakly, I heard of the Song disaster, so I knew that there was a heavenly path, why?). To say, the fire of the ancients is right, or eating in the heart, or eating in the heart, to produce the inner fire, is therefore the fire of the quail, and the heart is the fire. The fire of the Tao Tang clan is in the Shangqiu of Fu Bo, the great fire, and the fire is timely. Because of this, the merchants were on fire. See Spring and Autumn Left Transmission of Justice). Other small countries have other ways of fixing the vernal equinox. For example, in the tanguo people in the coastal areas of Shandong Province, the initial arrival of the observer Yan every year is to measure the arrival of the spring equinox. The Zuo Chuan mentions that when the emperor of the State of Tan arrived in the State of Lu, he told Lu Zhaogong that his ancestor Shao Hao, in the Xia and Yin dynasties, named officials by the name of birds, and called Xuan Bird the lord of the "points" to show respect for Jia Yan (Zuo Chuan, in the seventeenth year of Zhao Gong," "Autumn, Tan Zi came to the dynasty, and the gong feasted with him. Shōko asked, "Why did the young bird official of the Shōga clan do the same?" Tan Zi said: "My ancestors are also ,...... I am a high ancestor of the youngest, the phoenix is suitable, so the age is in the bird, for the bird master and the bird name. The Tori tori clan, The Risho Clan, the Gentori clan, the Divisional One also"). This statement shows that three or four thousand years ago, Jia Yan formally came to Tan at the spring equinox, and Tan Guo used this as a precursor to the beginning of agriculture. We now have a phenological observation network, which, in addition to other observations, also pay attention to the coming and going of the swallow. According to phenological observations in recent years, Jiayan is going to Shanghai near the spring equinox, and tai'an and other places in Shandong Province ten to twelve days later. Tan lives between Shanghai and Tai'an. According to E· S· Wilkinson wrote in his book Birds of Shanghai: "The swallow came to the lower Reaches of the Yangtze River and Shanghai on March 22, and this is the case every year. [8] Obviously, three or four thousand years ago, Jia Yan had already arrived in Tanguo at the spring equinox, and now on the day of the spring equinox, Jia Yan can only go to Shanghai. It makes sense to compare the two sites from the same period (1932-1937) to see how different they are.
The climate of the Zhou Dynasty, although initially warm, soon deteriorated. The Bamboo Book Chronicle records that during the reign of King Xiao of Zhou, a large tributary of the Yangtze River, Hanshui, was frozen twice, occurring in 903 and 897 BC. The Chronicle also mentions that after the ice, there was a great drought. This indicates the coldness of the tenth century BC period. This is also confirmed by the Book of Verses. According to legend, the Book of Poetry and the Wind of Poetry was written during the reign of King Chengwang of the early Zhou Dynasty (1063-1027 BC), and may have been written shortly after becoming a king. The location of the feng is said to be an area not far from Xi'an, 500 meters above sea level. The important phenological events of the year at that time can be seen in the following verses in the "Wind":
Dates are peeled in August and rice is harvested in October.
For this spring sake, to introduce mei shou.
Then he said:
On the second day, the ice rushed through, and the third day was absorbed in Lingyin.
On the day of the fourth day, the fleas are sacrificed, and the leeks are sacrificed.
Frost in September, polyester in October.
These verses can be used as a phenological calendar for the early Zhou Dynasty, that is, the 10th and 11th centuries BC. If we compare the phenology in the Feng Feng with the phenology in other national styles in the Book of Poetry, such as the phenology in Zhao Nan or Wei Feng, we will feel the cold of the land. "National Wind · Zhao Nan" poem Yun, "There are plums, and there are baskets." "Wei Feng" Shiyun, "Zhan Pi Qi'ao, Green Bamboo Yiyi." Plums and bamboo are subtropical plants, which proves that the climate was harmonious and warm at that time, which was very different from the phenology of "Feng Feng". This difference between cold and warm is partly due to the high altitude of the land, and on the other hand, due to the cold of the early Zhou Dynasty, as recorded in the Bamboo Book Chronicle, and the phenology of this cold period recorded in the Feng Feng. In conjunction with this, the lunar calendar at the beginning of the week is based on the December of the current solar calendar, so the August of the "FengFeng" is equal to the ninth month of the solar calendar, and so on (some people think that Zhou Zhengjianzi should be two months away from today's solar calendar. But "Zhou Jianzi" is just a traditional saying. According to the "July Flowing Fire" in the "Wind of The Wind", the precession calculation of the position of the Great Mars, and the calculation of the eclipse in the Spring and Autumn, can determine that the calendar from the beginning of the Zhou To the beginning of the Spring and Autumn period is Jianugou, not Jianzi.
The cold conditions in the early Zhou Dynasty did not last long, only about a century or two, and then warmed up again during the Spring and Autumn Period (770-481 BC). The Zuo Zhuan often mentions that the Shandong Lu kingdom spent the winter and the ice house did not get ice; this was especially the case in 698, 590, and 545 BC. In addition, subtropical plants such as bamboo and plum trees are often mentioned in the Zuo Zhuan and the Book of Poetry.
Since the Song Dynasty (960-1279 AD), plum trees have been cherished by the people of the whole country, calling plums the leader of flowers, and Chinese poets have generally chanted. In fact, after the Tang Dynasty, mei in North China was invisible. However, in the middle of the Zhou Dynasty, the lower reaches of the Yellow River Basin were everywhere, and Mei was mentioned five times in the Book of Poetry alone. In "Qin Feng", there is "Where is the end of the south?" There is a plum" verse. Zhongnan Mountain is located in the south of Xi'an, and now there are no plum trees whether wild or cultivated (according to the investigation of comrades such as Xin Shuzhi of Shaanxi Wugong Northwest Agricultural College. Regarding the phenological materials in xi'an Wugong in this article, the comrades of the Northwest Agricultural College of the whole department are supplied, and I hereby thank you. ）。 It should be pointed out below that since the Song Dynasty, the North China plum tree has not existed. During the Shang and Zhou Dynasties, the plum tree fruit "plum" was a daily necessity, as important as salt, and used to harmonize the diet and make it palatable (because vinegar was not known at that time). The Book of Books · The Second Book of Sayings says, "If you make wine, you will only be a rice stick; if you are a soup, you will only be salted and plum." This shows that during the Shang and Zhou Dynasties, plum trees were not only common, but also widely used in daily life.
By the Warring States period (480-222 BC), the warm climate continued. From the situation of food crops mentioned in the Book of Poetry, it can be concluded that from the Western Zhou Dynasty to the Spring and Autumn Period, the people of the Yellow River Basin planted millet and millet as the main food. But during the Warring States period, they subsisted on millet and beans. Mencius mentions that only the northern tribal breeds. This change is probably mainly due to the improvement of agricultural means of production, such as the invention and use of iron farming tools. Mencius also said that at that time, agricultural cultivation in the Qilu area could be ripened twice a year. Xunzi, later than Mencius, confirmed the incident. XunZi said that in his time, a good cultivator could produce two crops a year. Xun Zi was born in the south of present-day Hebei Province, but spent most of his time working in Shandong Province, south of Shandong and north of Jiangsu. In recent years, until liberation, in the north of the Huai River, it is customary to plant three crops in two years, and the season is too short to plant two crops a year. The twenty-four solar terms were determined by the climate of the Yellow River Basin observed during the Warring States period. At that time, the frost was set on the twenty-fourth day of the tenth month of the solar calendar. Now the first frost in autumn in Kaifeng and Luoyang (Zhoudu) is around November 3rd to 5th. Rain Festival, warring states time is set for February 21. The final frost period around Kaifeng and Luoyang is now around march 22. In this way, the growing season is now thirty or forty days longer than in the Warring States period. All this shows that during the Warring States period, the climate was much warmer than it is now.
By the Qin Dynasty and the Former Han Dynasty (221 BC to 23 AD), the climate continued to be mild. According to legend, there are many phenological materials in the "Rendi Chapter" in the book "Lü Shi Chunqiu" compiled by Qin Lü Buwei. In the book "Nongdan" written by Zhang Biao in the early Qing Dynasty (1660 AD), it is said that the "Lü's Spring and Autumn" Cloud: "After the winter solstice, the seven days of calamity were born. Sora, Mr. Hyakusa no. So the plough began. Today, the northern land is cold, there are sixty or seventy years after the winter solstice and the cangpu has not yet developed", according to Zhang Biao, the phenology in early spring in the Qin Dynasty was three weeks earlier than in the early Qing Dynasty.
During the reign of Emperor Liu Che of the Han Dynasty (140-87 BC), Sima Qian composed the Records of History, in which the "Chronicle of Cargo Breeding" described the geographical distribution of cash crops at that time: "Shu Han Jiangling Thousand Trees oranges; ... Chen Xia thousand acres of lacquer; Qilu thousand acres of mulberry; Weichuan thousand acres of bamboo. According to the orange, lacquer, bamboo are all subtropical plants, at that time the breeding places such as orange in Jiangling, mulberry in Qilu, bamboo in Weichuan, lacquer in Chen Xia, have been in the north of the current distribution limit of such plants or beyond the northern boundary. A reading of the distribution map of plants in China today shows that the northern boundary of subtropical plants at the time of Sima Qian was pushed north than it is now. In 110 BC, the Yellow River broke through at the mouth of the Yellow River, and in order to seal the mouth, the bamboo of the Qiyuan Garden in Henan was cut down and woven into a container to contain stones to block the mouth of the Yellow River. It can be seen that at that time, the bamboo in the area of Henan Qiyuan was very luxuriant.
By the beginning of the Eastern Han Dynasty, that is, at the beginning of the Common Era, China's weather had a tendency to become cold, and there were several times when the winter was severely cold, and in the late spring, the capital of the country, Luoyang, also fell frost and snow, freezing to death many poor people. However, the cold period of the Eastern Han Dynasty was not long. At that time, the astronomer and literary scholar Zhang Heng once wrote "Nandu Fu", which contained the sentence "Tang Orange Deng Tangerine", indicating that oranges and oranges were still very common in southern Henan Province. Until the Three Kingdoms period, Cao Cao planted oranges in Tongquetai, only flowering and not bearing fruit, and the climate was colder than that of the aforementioned Han Wudi era. Cao Cao's son Cao Pi inspected the exercise of more than 100,000 soldiers in Guangling (present-day Huaiyin) on the Huai River in 225 AD, but due to the severe cold, the Huai River suddenly froze and the exercise had to be stopped. This is the first recorded ice freeze on the Huai River that we know of. The climate was colder then than it is now. This cold climate continued until the second half of the third century, especially in the decade 280-289 AD, when frost fell every year in April of the lunar calendar (equal to May of the solar calendar). Xu Zhongshu once pointed out that the climate of Han and Jin was different, and the average annual temperature at that time was about 1 to 2 °C lower than now.
During the Southern and Northern Dynasties (420-589 AD), China was divided into north and south, bounded by the Qinling Mountains and the Huai River. Due to the Civil War and the continuous wars between the various ethnic groups in the north, the historical record is relatively poor. The establishment of an ice house by the Southern Dynasty in Nanjing's FuzhouShan is an interesting event of climatic significance. The ice house was a building prepared by various dynasties since the Zhou Dynasty to preserve food fresh and prevent it from decay. Before the Southern Dynasty, the capital was located in the Yellow River Valley of North China, and it was not a problem to build ice houses in winter to store ice, but the capital of the Southern Dynasty was in Jianye (present-day Nanjing), and the ice houses in Nanjing Covered Zhoushan were to be equipped with ice every year, and the situation was different. The question is where does the ice come from? At that time, the north of Huanghuai was an enemy area, and it was impossible to supply ice; the method of artificial ice making was not possible at that time; if the winter temperature in Nanjing was the same as today, the rivers and lakes near Nanjing would not freeze for a long time, and the ice cubes were not thick enough to be stored. During the period from 1906 to 1961, the average temperature in the first month of Nanjing was +2.3 °C, and only in 1930, 1933 and 1955 it fell below 0 °C. Therefore, if the Nanjing Zhoushan Ice House in the Southern Dynasty era was a reality, then the winter in Nanjing at that time was about 2 °C colder than it is now, and the average annual temperature was 1 °C lower than it is now.
Around 533-544 AD, Jia Sixun of the Northern Dynasty wrote a sixth-century agricultural encyclopedia, Qi Min Zhishu, paying close attention to the phenological properties of the region at that time. He said: "Fan Gu: There are early and late maturities, seedlings are high and low, how many ,......, harvest is good, the amount of land is favorable, then the force is less and the success is more." Let the love return, labor and no gain. "This book represents the most comprehensive knowledge of Chinese agriculture before the Six Dynasties. Recently, Chinese farmers and Japanese scholars have taken the book seriously. Jia Sixun was born in Shandong, and his book is a record of agricultural practices in North China and north of the Yellow River. According to the book, apricot blossoms bloom in the third month of the lunar calendar (mid-April of the solar calendar), and in the first month of april (about the beginning of may in the solar calendar), the jujube tree begins to bear leaves, and the mulberry flowers are adjusted. If we compare this phenological record with recent observations in the Yellow River Basin, we can see that the apricot blossoms and jujube trees in the sixth century bloomed four to two weeks late, which is roughly similar to the phenology of present-day Beijing. Regarding the cultivation of pomegranate trees, the book says: "In the middle of October, it is wrapped in puddle, and if it is not wrapped, it freezes to death." The beginning of February was liberation. "Now in Henan or Shandong, pomegranate trees can grow outdoors and do not need to be buried in winter, which indicates that the climate in Henan and Shandong in the first half of the sixth century was colder than it is now."
The end of the sixth century to the beginning of the tenth century was the era of the unification of the Sui and Tang Dynasties (589-907 AD). China's climate became warmer by the middle of the seventh century, and in the winters of 650, 669 and 678 AD, the capital Chang'an was snow-free and ice-free. In the early eighth century, plum trees grew in the Imperial Palace. During the reign of Emperor Xuanzong of Tang and Li Longji, concubine Jiang Caiping was called Concubine Mei because her residence was full of plum blossoms. At the beginning of the ninth century, plum blossoms were still planted in Qujiang Pond on the southern outskirts of Xi'an. The poet Yuan Shu talked about the plum of Qujiang. At the same time, citrus is also cultivated in Chang'an. The Great Tang poet Du Fu mentioned that Li Longji planted oranges in Penglai Temple, saying that in the autumn of the Tenth Year of Tianbao (751 AD), there were several citrus trees in the palace that bore one hundred and fifty fruits, and the taste was the same as the tribute citrus in Jiangnan Shu Province. Tang Leshi's "Biography of Yang Taizhen" is more specific. He said that in the last year of the new century, Jiangling entered citrus, and Li Longji planted it in Penglai Palace. Tianbao was strong in September of the tenth year, and more than one hundred and fifty were given to Zaichen. During the reign of Emperor Wuzong (841-847 AD), citrus was also planted in the palace, and once the orange tree bore fruit, Emperor Wuzong asked the eunuch to reward the ministers with three oranges each. It can be seen that from the beginning of the eighth century to the middle of the ninth century, Chang'an could grow citrus and bear fruit. It should be noted that citrus can only resist the minimum temperature of -8 ° C, and plum trees can only resist the minimum temperature of -14 ° C. Between 1931 and 1950, the annual absolute minimum temperature in Xi'an fell below -8 °C per year, and in three of the twenty years (1936, 1947 and 1948) it fell below -14 °C. Plum trees do not grow well in Xi'an, which is the reason, there is no need to say oranges and oranges.
During the Tang Dynasty, the growing season also seemed to be longer than it is now. Around 862 AD, Fan Shu wrote the Book of Barbarians that south of Qujing (latitude 24° 45' N; longitude 103 ° 50' E), west of Dianchi Lake, the people harvested two crops a year, rice in September, wheat or barley in April. Farmers in the Qujing area now have difficulty cultivating the same way because they find that the growing season is too short and have to grow peas and beans instead of wheat and barley (according to the Yunnan Meteorological Bureau in 1966).
After the fall of the Tang Dynasty, China entered the Five Dynasties and Ten Kingdoms Era (907-960 AD). There is no phenological material to base it in these turbulent times. It was not until the Song Dynasty (960-1279 AD) that it was unified, and the capital of the state was built in Kaifeng, Henan Province. The early Song Dynasty poet Lin Kui lived in seclusion in Hangzhou and was named after his Yongmei poems. The plum blossom is pushed to be the largest of the flowers because of its earliest flowering in the year, but in the early eleventh century, there were no plum trees in North China, and its situation was similar to that of modern times. Plum trees can only survive in the royal gardens of Xi'an and Luoyang and in the private cultivation gardens of rich families. In his poem, the famous poet Su Shi lamented that Mei had disappeared in Guanzhong. Su Shi's apricot blossom poems have "Guanzhong Xing Wumei, Lai Ru Chong Dinghe". At the same time, Wang Anshi ridiculed northerners for often mistaking plums for apricots, and his poems on red plums have the sentence "Northerners did not know each other at first, and they looked at apricot blossoms". From this phenological common sense, we can see the difference between the two dynasties of the Tang and Song dynasties.
At the beginning of the twelfth century, when China's climate intensified and turned cold, the Jin people invaded North China from the northeast to replace the Liao people, occupying the area north of the Huai River and the Qinling Mountains, with the current Beijing as the capital. The capital of the Song Dynasty (Southern Song Dynasty) was moved to Hangzhou. In 1111 AD, it was first recorded that Taihu Lake, which has an area of 2250 square kilometers between Jiangsu and Zhejiang, not only froze, but also solid enough to open to traffic. The cold weather froze all the famous citrus in Dongting Mountain, Taihu Lake. Snowfall in the capital, Hangzhou, is not only more frequent than usual, but also extends into late spring. According to the historical records of the Southern Song Dynasty, from 1131 to 1260 AD, the Spring Festival in Hangzhou snowfall, the average latest date of snowfall every decade is April 9, which is almost a month later than the date of the last spring snow in the first decade of the twelfth century. From 1153 to 1155 AD, when the Jin Dynasty sent envoys to Hangzhou, the canals near Suzhou were often frozen in winter, and the boatmen had to often prepare hammers to break the ice to open the way. In 1170 AD, the Southern Song Dynasty poet Fan Chengda was sent to the Jin Dynasty, and he went to Beijing on the ninth day of the ninth month of the lunar calendar, that is, the Chongyang Festival (October 20 of the solar calendar), when the western mountains were full of snow, and he wrote poems to commemorate it. The South Canal near Suzhou freezes in winter and snows everywhere in October in the Xishan solar calendar near Beijing, which is extremely rare now, but seemed common in the twelfth century.
In the twelfth century, cold climates were also prevalent in southern China and southwestern China. Lychee is a fruit tree widely cultivated in Guangdong, Guangxi, southern Fujian and southern Sichuan, and is one of the typical tropical fruits of great economic significance. Derived from the tropics, lychee is more susceptible to freezing to death in colder climates than oranges, and it can only resist the maximum temperature of about -4 °C. In early 1955, a severe cold wave occurred along the east coast of China, which caused great disasters to Zhejiang citrus and Fujian lychee. According to Li Lairong's book "Research on Lychee Longan", Fuzhou (latitude 26° 42 ′ E 119 ° 20 ′ E) is the northern limit for the growth of lychees on the east coast of China. The people there have been cultivating lychees on a large scale since at least since the Tang Dynasty. For more than a thousand years, the lychees there have suffered two total deaths: once in 1110 AD and once in 1178 AD in the twelfth century.
The Tang Dynasty poet Zhang Shu 's "Chengdu Qu" poem, poem Yun: "Jinjiang near the west smoke and green water, Xinyu Mountain head lychee ripe". Zhang Wenchang's "Chengdu Song" Yun: "The Jinjiang River is near the west of the smoke and water is green, and the lychees on the Xinyu Mountain are ripe." There are many restaurants along the Wanli Bridge, and tourists love to stay with whom. 'This has not tasted chengdu also. Chengdu has no mountains and no lychees. Su Huangmen Shiyun: "Shuzhong lychee out of Jiazhou, the rest and eyebrows are not." Lu You only knows that there were no lychees in Chengdu during the Song Dynasty, but it does not prove that there were no lychees in Chengdu in the Tang Dynasty), indicating that there were lychees in Chengdu at that time. During the Song Dynasty, Lychees could only be born in his hometown of Meishan (60 kilometers south of Chengdu) and Leshan, 60 kilometers further south, and in his poems and the poems of his brother Su Rui, it is stated that Lu You and Fan Chengda lived in Sichuan for some time during the Southern Song Dynasty, and paid great attention to the distribution of lychees. From Lu You's poems and Fan Chengda's book "Wu Chuanlu", in the twelfth century, Meishan, Sichuan, no longer produced lychees. As a cash crop, only Leshan still has old trees with large wooden wheels. Lychee was only planted in large quantities along the Yangtze River in southern Sichuan, such as Yibin and Huzhou. Now Meishan can still grow lychees, but it is not used as a cash crop. There is a lychee tree in Sudongpo Park, which is said to be about a hundred years old. The lychee fruit in the Meishan market now comes from Leshan in the south of Meishan and Huzhou in the southeast. This proves that today's climatic conditions are more like the Northern Song Dynasty and warmer than those of the Southern Song Dynasty. Judging from the date of the last snowfall of the Spring Festival in Hangzhou, the average temperature in Hangzhou during the Southern Song Dynasty (twelfth century) was 1 to 2 °C colder than it is now.
Although Japan is separated from China by a vast sea of 400 kilometers, the phenology recorded by Japan can still be compared with that of China. Japan has a valuable record of phenological observations. After the ninth century, Japanese emperors and feudal lords held banquets in Saikyo Garden to celebrate the bloom of cherry blossoms in Japan, and the date of celebration was recorded until the 19th century. These accounts can be compared with the current records of the Emperor.
This suggests that, in about a thousand years of records, the average date of cherry blossom blooming in Kyoto is the earliest in the ninth century and the latest in the twelfth century. During this time, the climate changes in China and Japan were consistent. However, by the seventeenth century, in China, it was the end of the Ming Dynasty and the beginning of the Qing Dynasty, the climate was very cold, and the cherry blossoms in Japan bloomed earlier than they are now, and the reason for this is still unexplained.
Just after the end of the twelfth century, winter temperatures in Hangzhou began to warm up again. In 1200, 1213, 1216 and 1220, Hangzhou was free of any ice and snow. During this period, the famous Taoist priest Qiu Chuji lived in the Changchun Palace in Beijing for several years. In 1224 AD, he composed the poem "Spring Tour": "During the Qingming Dynasty, apricot blossoms bloom, and thousands of households come and go every day." "It can be seen that the phenology of Beijing at that time was the same as that of Beijing today. This warm climate seems to have continued into the second half of the thirteenth century, as evidenced by the distribution of bamboo in Northern China. During the Sui and Tang dynasties, Hanoi (present-day Bo'ai, Henan Province), Xi'an and Fengxiang (Shaanxi Province) had special official offices to manage bamboo gardens, called the Bamboo Supervision Division, and in the early Southern Song Dynasty, only the Bamboo Supervision Division of Fengxiang Province remained, and the Bamboo Supervision Divisions in Hanoi and Xi'an were cancelled due to lack of production. At the beginning of the Yuan Dynasty (1268-1292 AD), Xi'an and Hanoi re-established the official yamen of the "Bamboo Supervision Division", which was the result of a warmer climate. However, after a short period of time, it was stopped again, and only Fengxiang's bamboo cultivation continued until the early Ming Dynasty. This history of bamboo cultivation shows that after the fourteenth century, that is, after the beginning of the Ming Dynasty, bamboo was no longer cultivated as an economic forest north of the Yellow River.
The warmer periods of the early and mid-thirteenth centuries were brief, and soon the winter was cold again. According to the diary of Guo Tianxi, a Yang man from Jiangsu Province, at the beginning of the first month of 1309 AD, he took a boat home along the canal from Wuxi to the canal and froze the canal and had to leave the ship ashore. There is a manuscript in the Zhejiang Provincial Library in Hangzhou, and only two months of diaries from the winter of 1309 AD remain. In 1329 and 1353 AD, Taihu Lake was frozen, several feet thick, and people could walk on the ice, and the oranges froze to death. This is the second and third record of icy formation in Taihu Lake. In the collection of poems of the Mongolian poet Qi, there is a poem describing the repair of the embankment of the Yellow River in Baimao, Shandong Province, in 1351 and the ice cubes drifting down the Yellow River in November of the same year, which interfered with the repair work. There are "Ministers miscellaneously discuss baidu water, set up officials to open the house Linqingxu, when the sub-prison comes in October, the river ice saichuan rain and snow, adjust the husband 100,000 to build a new valley, the blood of the hands and feet is cracked, the supervision of the order is like a thunderstorm, the cold day is short and difficult for the merit" Yunyun). Recent records of the Yellow River Basin Water Conservancy Station indicate that it was not until December that ice cubes appeared in the rivers in Henan and Shandong. It can be seen that the early winter ice cubes of the Yellow River appeared one month earlier than now. Nai Xian lived in Beijing for several years, and in one of his poems about Jia Yan, "The end of March (the end of april in the solar calendar) is the end of the month, and the autumn (the sixth and seventh days of the eighth month of the solar calendar) is to go", staying for such a short time, compared with the current phenological record, to come and go for a week shorter. From the above phenology, the fourteenth century is colder than the thirteenth century and the present. In the thirteenth and fourth centuries, the changes in China's phenology and the Japanese cherry blossom phenology were in line with each other.
The cold temperature of the climate can also be determined by the height of the snow line on the top of the mountain. When the climate is cold, the snow line will be lowered. In the twelfth and third centuries, the snow line in the Tianshan Mountains in northwest China seemed to be lower than it is now. The Journey to the West of the Changchun True People records that Qiu Chuji, at the invitation of Genghis Khan, traveled from Shandong to Samarkand via Mongolia and Xinjiang, and passed through Sailim Lake near Santai Village on October 8, 1221 (solar calendar). Qiu Chuji said in his travelogue, "The big pond is several hundred miles in circumference, the snow peak rings, the reflection pool, the name is tianchi." The altitude of this lake is 2073 meters, and the highest peak around the lake is about 1500 meters higher. On September 14 and 16, 1958, the author passed through Lake Sailim twice, and there was no snow at the top of the mountain. At present, the snow line of the Tianshan Mountains is located between 3700 and 4200 meters, and considering the season when Qiu crossed this place, if the top of the mountain has been covered by the annual snow line, the snow line at that time was about 200 to 300 meters lower than it is now. In recent years, Chinese geomorphologists have found that the eastern section of The Tianshan Mountains is 3650 meters above sea level, completely uneroded, and it seems that it is a newly left final moraine. This may be a legacy of the Cold Ages of the twelfth and eighteenth centuries, what Western Europeans call the modern "Xiaoice period." This cold period in China in the twelfth and third centuries (the Southern Song Dynasty) seemed to foresee the cold in Europe in the next two centuries. According to research, in the Russian plains of the European part, the cold period began around 1350 AD; in the German and Austrian regions of central Europe, H. Flohn thought that the years 1429-1465 AD were the beginning of a clear deterioration of the climate: in England, H. H· Lamb thought that the English famines of 1430, 1550 and 1590 were caused by cold weather. It can be seen that China's cold period, although not necessarily consistent with Europe, the same beginning and end, but still closely related. It is possible that the cold current began in East Asia and gradually moved westward to Western Europe.
Temperature changes in China's history (source network)
<h1 class="pgc-h-arrow-right" data-track="336" > Fangzhi period (1400-1900 AD).</h1>
In the Ming Dynasty (1368-1644 AD), that is, after the fourteenth century, due to the large number of various poems, history books, diaries, and travelogues, phenological materials were scattered everywhere, even if a small part of the collection was beyond the reach of a single person's energy. Fortunately, most of this material is collected in the local chronicles compiled by the provinces and counties. There are more than 5,000 kinds of local chronicles in China. These chronicles, in addition to the instrument-side climate records, provide reliable historical data for the climate of a region. The phenological material described in the previous section is limited to biological evidence, such as the relationship between climate on plant growth and animal distribution, and the impact on the agricultural practices of local people, which can only be used as a hint, and rarely directly confirm that the climate is indeed different from the present. Weather disasters are directly related to climate, and we have more evidence when we have past climate data compared with current climate data.
In various climate disasters, we use the abnormal harsh winter as the criterion for judging the climate of a period. It is an unusual thing for rivers and lakes that do not freeze in normal years to become frozen. Ice and snow are not visible in the world on tropical plains, and this is also an anomaly once the tropical plains snow freeze in winter. This section discusses the emergence of these two anomalous climates. The three largest freshwater lakes in China are Poyang Lake, with an area of 5,100 square kilometers, Dongting Lake with 4,300 square kilometers, and Taihu Lake with 3,200 square kilometers. All three lakes are connected to the Yangtze River. Poyang Lake and Dongting Lake are located around 29° north latitude, and Taihu Lake is located between 31° and 31° 30′ north latitude. For river freezing, we use the Huai River in Xuyi, Jiangsu Province, and the Xiangyang HanShui in Hubei Province as the standard. Xu Jinzhi of the Nanjing Institute of Geography once made statistics on the ice age of the rivers and lakes in the Yangtze River Basin and the number of years of snow and frost in the tropical areas near sea level according to the Fang Zhi of the areas around these rivers and lakes, and the two statistics shared a total of 665 kinds of Fang Zhi. For snowfall in the tropics, only reference is made to the Fang Zhi of Guangdong Province and Guangxi Zhuang Autonomous Region. The tropical regions of Yunnan are not included due to their high altitude.
There is little information from before the thirteenth century, and there are many fragments, so it is listed only as a line. The climate has been mild since the twentieth century, until 1970, when the rivers and lakes were only frozen once, so it was only listed as a row. After the fourteenth century, the data is listed in the table according to a quarter of the first century (snowfall in the tropics began in the sixteenth century). At the same time, the number of mild winters and the number of icing days in each quarter of the century of Lake Suwa (36° N, 138° east) in Japan are compared in Table 6 [24]. The last line of Table 6, the date of icing of Lake Suwa.
In these five hundred years, the number of cold years in our country is not evenly distributed, but arranged in groups. Warm winters were between 1550-1600 and 1770-1830 AD. Cold winters were between 1470-1520, 1620-1720 and 1840-1890 AD. In the century, the seventeenth century was the coldest, with a total of fourteen severe winters, followed by the nineteenth century, with a total of ten severe winters. Although the rivers and lakes of China listed are located in the subtropical region between latitude 29 and 32° north, and the snowfall date is limited to the tropical region, the cold temperature procedures shown in Tables 4 and 5 also coincide with each other. This is because the ice of the three lakes and the Huaihan River, and the snowfall in Guangdong and Guangxi, are due to the particularly cold and cold currents in Siberia or Mongolia. According to Ye Duzheng's research at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, this cold wave is mainly the result of Europe's eastward movement by blocking the split of high pressure.
Compared with the records of Lake Suwa in Japan, the climate of China and Japan is nearly the same. Both series indicate that there were more severe winters in the seventeenth century, but the harsh winters in Japan began and ended about a quarter of a century earlier than in China. For example, the lake began to be cold in the seventeenth century from 1626 to 1650 AD, while in China it did not chill until 1651-1675 AD. Lake Suwa was already cold at the end of the fifteenth century, and China was not cold until the beginning of the sixteenth century, but by the second half of the nineteenth century there was an irreconcilable phenomenon: China was very cold at that time, and Lake Suwa was unusually warm. This incongruity is noteworthy by the authors, as mentioned in Tatsuo's book Climate in Japan. He said that during the period of Lake Suwa's records, a hot spring spewed a large amount of warm water into Lake Suwa, which may have warmed Lake Suwa and prevented it from freezing in the winter in the following period. Lake Suwa is only 14.6 square kilometers, so it is susceptible to some local factors.
Comparing the trend of winter temperature in China with the trend of winter temperature in Europe, the consistency is smaller than that of Japan. In Europe, the mild winter between 1150 and 1300 AD was the most pronounced, while the twelfth century in China was the most common century of severe winters. China's cold winters of the seventeenth century were the same as those of Russia, Germany, and Britain in Europe, but not in the same decade. It is consistent that the cold and mild winters of the two places have maintained a condition for fifty years and have changed from each other. Half a century of cold and warm changes have emerged, as has China and Europe. This is related to the overall atmospheric circulation change, especially the amount and strength of the blocking high pressure mentioned above.
Above we have only talked about the relative coldness of winter between the fifteenth and nineteenth centuries, and we are ready to talk about the impact of climate change on humans, animals and plants during this period. During this period, one thing seems to be clear, that is, during this warmest period of five hundred years (1400-1900 AD), the climate did not reach the warmth of the Han and Tang dynasties. During the Han and Tang dynasties, plum trees grew all over the Yellow River Basin. In many of the Fangzhi of the Yellow River Basin, there are several places named to commemorate the previous plum trees there. For example, there is Meikeling in the northwest of Shaanxi County (36° north latitude, 109 ° 20'E longitude), which is named after the plum tree in the Tang Dynasty ("Yanzhou Zhi Shan Chuan", Qing Dao Guang Shi Xiu). There is a small hill in the northern seven miles of the prefecture in Pingdu (36° 48′ N, 113 ° 40′ E) in Shandong, called Jingpo, which is said to have been planted with plum trees ("Laizhou Fuzhi ShanChuan", repaired during the Qianlong Qing Dynasty). See also "Pingdu Prefecture Chronicle of Mountains and Rivers", Qing Dao Guang Shi Xiu). At present, there are no plums in Yanzhou and Pingdu. Thirty miles southwest of Zhengzhou, Henan (34° 50' north latitude, 113 ° 40 'E longitude), there is Meishan Mountain, which is tens of thousands of feet high, and the number of weeks is counted, and it is famous for many plum blossoms in the past ("Zhengzhou Zhi · Youdi Zhi" "Mountains and Rivers"). There are no plums anymore. After liberation, the Zhengzhou Municipal People's Government has been successful in planting plum trees in Zhengzhou People's Park. Zhengzhou in 1951-1959, the absolute minimum temperature per year above -14 °, can be said to be the northernmost limit of the current plum tree.
For reference, here is a reference to the history of grape cultivation in Europe. Between 1100 and 1300 AD, vineyards were widely distributed in southern England and parts of Germany. As a result of the subsequent harsh winters, especially the severe winter of 1430 AD, the minimum temperature dropped to -20° to -25°C, and the vine cultivation stopped completely. This cold period lasted until the beginning of the twentieth century when it began to warm up. Between 1920 and 1950 AD, the average annual temperature rose by half a degree to one degree, and the growing season was extended by two or three weeks compared with the eighteenth century; fruit crops such as grapes, apricots, and peaches. It was planted again in the south of England. The longest record of phenology in the UK is that of five generations of descendants of the Marshall family in Norfolk, which began in 1736 AD and continued to be observed for 190 years. In early spring, anemone flowers bloomed 21 days earlier from 1891 to 1925 AD than in 1751-1785 AD. It is known that England was much warmer at the beginning of the twentieth century than it was in the eighteenth century.
During these five hundred years, the coldest period in our country was in the seventeenth century, especially from 1650 to 1700 AD. For example, the orange and citrus orchards in Jiangxi Province, which have paid tribute to the government every year since the Tang Dynasty, were completely destroyed in two cold snaps in 1654 and 1676 AD (Ye Mengzhu, ed., Reading the World, in Ye Jingyuan's Selected Works of Chinese Agronomy, 45 pp., the fourteenth "citrus" of the four categories). During this fifty-year period, Taihu, Hanshui and Huaihe all froze four times, and Dongting Lake also froze three times. Poyang Lake is large, located to the south, and once frozen. In the tropics of our country, snow and ice have also been extremely frequent in this half century.
In the past five hundred years, China's phenological materials are voluminous, which cannot be summarized in this article. In order to compare them with the phenological materials before the fourteenth century, only the two coldest phenological materials seen in the seventeenth-century notes have been selected for discussion. One is the Diary of Yuan Xiaoxiu [29]. Between the 36th and 45th years of the Ming Dynasty (1608-1617 AD), Yuan Xiaoxiu stayed in the diary near Shashi, Hubei Province. The other is the "Journey to the North" written by the people of Hangzhou in the Qing Dynasty. Describes what he saw and heard in Beijing between 1653 and 1655. These two books detail the dates of early spring flowers of peaches, apricots, cloves, and begonias. From the records of these two people, we can calculate that the phenology of the early spring when Yuan Xiaoxiu was seven to ten days later than that of wuchang phenology today. Compared with today's Beijing phenology, which is recorded in Tanqian, it is also one or two weeks later. It is even more noteworthy that in the middle of the seventeenth century, the freezing period of the Tianjin Canal was much longer than it is today. In 1653, Tan Qian came to Beijing from Hangzhou, and when he arrived in Tianjin on November 18 of the solar calendar, the canal was frozen; by November 20, the river ice was even stronger, so he had to drive to Beijing. In 1655, on the fifth day of the third month of the solar calendar, when Tanqian departed from Beijing to return to Hangzhou, the Beijing Canal began to thaw. According to the account of Tan Qian, it can be seen that the canal freeze period at that time lasted for 107 days a year. The Institute of Hydrology of the Ministry of Water and Power compiled records made by Yangliuqing Station near Tianjin from 1930 to 1949, and during these two decades, the average annual freezing of canals was only 56 days, that is, the average date of freezing was December 26, and the average date of opening the river was February 20. According to Tan Qian's "Journey to the North", the date of the opening of the Beijing Canal at that time was on the day of the Sting Festival, that is, March 6 of the solar calendar, twelve days later than now. From the phenology sooner or later, the difference between the temperature of the two time can be calculated. According to the "law of bioclimatology" in phenology[31]: In early spring, in the eastern part of the temperate continent, the difference in latitude by one degree or height difference of 100 meters is four days. This shows from the isotherm chart that Beijing was 2°C colder in the winter of the mid-seventeenth century than it is now.
China's 5,000-year temperature change curve (source network)
<h1 class="pgc-h-arrow-right" data-track="335" > instrument observation period (from 1900 AD).</h1>
An anemometers and rain gauges were used before the Ming Dynasty, and it wasn't until 1911 that the Chinese government established regular weather stations. After the founding of New China, the meteorological industry has developed unprecedentedly, and a perfect network of meteorological forecast stations has spread throughout the country. Before 1900, only a few places in China had meteorological records. At the beginning of the Ming Dynasty, rain gauges were distributed in different parts of the country, and in 1424, Zhu Di (Ming Chengzu) ordered the local governor to report the rainfall to the imperial court every year to estimate the agricultural production in various regions, but this matter soon became a formality and then stopped.
During the Qing Dynasty (1644-1910 AD), beijing, Nanjing, Hangzhou and Suzhou had records of rainy days. Records of Beijing from 1724 to 1903 AD are still preserved in the Forbidden City. These records record only the beginning and end of the rainfall time, not the quantity; it is only observed with the naked eye, not measured by instruments. In 1932, these records were analyzed once and published as a report. According to this report, the average date from the first snowfall in autumn to the last snowfall at the end of the Spring Festival concluded that the period from 1801 to 1850 was warmer than the period from 1751 to 1800 before it and the period from 1851 to 1900 thereafter.
In 1593, Galileo of Italy invented the temperature gauge. Soon after, Jesuit priests introduced the temperature gauge to China. In the middle of the eighteenth century, the Jessa priest J. Amiot measured the daily minimum and maximum temperatures in Beijing from 1757 to 1762, and the results were published in the French journal, Volume VI. About a hundred years later, in 1867, the Russian Academy of Sciences in St. Petersburg dispatched H. Fritsche went to Beijing to establish a meteorological and geomagnetic station. He worked in Beijing for sixteen years and wrote the article "Climate in East Asia". These papers give us an idea of the annual average temperature and the average monthly temperature in Beijing during the eighteenth and nineteenth centuries. Strictly speaking, these old data cannot be compared with modern meteorological records, because the observation time and instrument placement methods are not the same as those of today (e.g. J· The thermometer used by Amiot is still a heat and cold gauge of The Liesch scale). Since these sources are the only records of temperatures in the eighteenth and ninth centuries, they can only be based on their original values.
In terms of the three months of winter, the temperature in the mid-twentieth century was significantly warmer. The average temperature in December, January and February was -2.8 °C, 0.9 °C higher than during the period 1875-1880 and 1.4 °C higher than in the mid-eighteenth century. However, the average temperature of the three summer months between 1954 and 1964 was significantly lower than that of the previous two periods. This may be due to the decline in continental climate in eastern China in recent years, while the oceanic climate has increased, as wind speeds have increased along the East Asian coast, increasing the impact of the ocean. This trend has also occurred in recent years along the north-eastern coast of North America; the Atlantic coastal currents have increased their vitality due to the increased temperature difference between the north and the south, which has increased the wind speed in the north-south direction, which has warmed up in the winter and the summer in northeast Canada.
In China, Beijing is the earliest thermometer to determine the air temperature, but the record is not complete, there is a large gap in the middle. In addition to Beijing, Shanghai, Hong Kong and Tianjin also have long-term recorded air temperatures. To compare the ancient temperatures of other countries, a ten-year slip average was made. Among them, Hong Kong lacks the temperature of the Second World War period, so it can only use the actual temperature of each year, and its disadvantage is that the curve is uneven, up and down, and it is impossible to see the trend of rising or falling temperature in this era. The ten-year moving average can correct this shortcoming. The curve shows that during the last twenty-five years of the nineteenth century, Shanghai's climate was very cold, about 0.5 °C lower than the average temperature of 4.6 °C in the winter (referring to December, January, and February, the same below) during the whole period. Around 1897, winter temperatures reached an average and subsequently exceeded the average. Stay above the average for about fourteen years. Around 1910 to 1928, the temperature gradually dropped below average. Winter temperatures then tended to rise again until 1945-1950, exceeding the average by 0.6°C. Thereafter, the temperature gradually decreased until it returned to the average in 1960. During this period, the winter temperature trend in Tianjin is also a wave-like swing parallel to Shanghai. However, the peak and bottom point arrived several years earlier than Shanghai and was also larger, while the peak and bottom point of the curve fluctuation in Hong Kong were more retarded than in Shanghai, and the range of sliding average temperature was smaller.
From the temperature records of Shanghai around 90 years, it can be seen that the temperature was the lowest during the last twenty-five years of the nineteenth century, and the highest in 1940. Comparing the ten-year average temperature (lowest in 1900 and highest in 1936) that slid between Shanghai and Alexandria and Cairo in the Arab Republic of Egypt at the same latitude, it can be found that during the period of decline or decline, Shanghai moved westward than Cairo; during the period of rise, Shanghai was later than Cairo, and the climate showed a trend of moving eastward.
During the more than 80 years of Shanghai's climate trend, some of them oscillate up and down to 0.5 °C or 1 °C, which is of great economic significance. It directly affects the growth of plants and animals, indirectly controls the occurrence of pests and diseases, and agricultural operations and agricultural production may be affected. Therefore, revisiting the past climate history, grasping the laws of climate change, and predicting the future climate change trend are of great significance for actively transforming the objective world.
In England, G· Manley has studied temperature records in central England from 1680 to 1960, with decadal slippage by quarter and year. It was found that from 1680 to 1690, during the period of low temperatures, the temperature trended upwards. Between 1880 and 1950, the upward trend in temperature was particularly pronounced. Since then, the temperature has dropped a bit. Compared with Shanghai and Tianjin, the winter temperature in England was after 1930, when the winter temperature in Tianjin and Shanghai was still rising, while the temperature in England showed a downward trend. From 1260 to 1814, the River Thames in London was completely frozen 23 times. One of the strongest and most accessible by horse was in the winters of 1309-1310 and 1688-1689. The River Thames has not been completely frozen since 1814. Leningrad in the SOVIET Union has a climate record of more than two hundred years since 1765. The Leningrad Geophysical Observatory has studied the annual sliding average temperature of this record, and proved that during this period, the average annual temperature in Leningrad was 3.9 °C, the coldest decade was 1780-1789, the average annual temperature was 2.8 °C, and the hottest decade was 1927-1936, with an average annual temperature of 5.4 °C. In terms of centuries, the first half of the nineteenth century is the coldest. Temperatures have been above the total average since 1890. It can be seen that the climate change obtained from the instrument records is more consistent in European countries, and there is a chronological priority with China.
During the past eighty years or so in China, temperature changes have affected the snow line and glacier advances in the Tianshan Mountains. According to the survey of the Glacier Snow Line Survey Team of the Chinese Academy of Sciences from 1960 to 1963, it is proved that in the fifty years from 1910 to 1960, the snow line of the Tianshan Mountains rose by 40 to 50 meters, and the glacial tongue of the Western Tianshan Mountains retreated by 500-1000 meters. The glacial tongue of the Eastern Tianshan Mountains retreats 200 to 400 meters. At the same time, the upper limit of the forest line has also been raised. Some findings suggest that the glaciers that now cover the peak of the Tian shan mountains are the product of the cold period of the historical era, which was formed during the cold period of about 1100-1900, rather than the remnants of the Quaternary ice age.
The average curve of ten years of slipping gives us a glimpse of climate change trends in a place. The disadvantage is that it masks individual harsh winters. Below we compare the average temperatures of tianjin, Shanghai and Hong Kong in the five coldest winters of the last 70 to 80 years. The lowest average winter temperature, although usually the most representative criterion for the cold of the entire season, is not always consistent with the greatest natural disasters encountered by plants and humans. During this period, the harshest weather in Central and Eastern China occurred in the first month of 1955; however, it was not listed in Table 8. Because in 1955, the harsh first month, followed by the warm February, so the temperature was not the lowest throughout the winter.
During the first month of 1955, there were successive cold waves from Siberia, and the record for the absolute lowest temperature in many parts of central and southern China was broken. This year, the Huai River near Zhengyang Pass froze from January 1 to February 15. The Han River also froze for twenty days from January 1 to February 20. Dongting Lake was completely frozen for three days from January 3 to 6. This is the only recorded event in the twentieth century when Dongting Lake, Hanshui and Huaihe rivers froze. This month's cold wave goes along the Beijing-Hankou Railway, so on this road, the temperature drop is the biggest. Lake Taihu is only partially frozen in East China. Frost falls in many parts of tropical China, even to the south of Hainan Island. Hundreds of thousands of acres of tropical trees were frozen to death, and Guangdong's winter sweet potatoes were completely destroyed this year.
During this period, another serious cold wave of human invasion was in February 1936, which was most affected by the cold wave in Tianjin. At that time, the Tianjin port and the outlet of the Haihe River were frozen from the beginning of February to the beginning of March. This is something that the elderly in the local area have not remembered in their lifetimes, and have not happened since. What is the reason for the freezing of Tianjin Port? First, due to the extremely low temperature in February 1936, the average temperature was -6.7 °C in January and -4.4 °C in February, which was 2.5 °C and 2.7 °C lower than the average temperature of the calendar year; second, due to the frequency of the east wind of 28.3%, which blocked the ice floes from entering the sea; third, due to the excess snow in Tianjin in February 1936 (the largest snow in February 1891-1949).
Why are some winters mild and cold waves rare, while others have too many winter cold waves? If severe cold snap seasons occur again during a certain period, then what is the reason for this cyclicality? Some meteorologists believe that the cycle of sunspots is related to the cycle of the climate. Japan and Tatsumi believe that the nineteenth century Japanese rice crops, due to the low summer temperature and poor growth of the years, seem to coincide with the largest years of sunspots. A. Poland Kosiba argues that "the extreme harsh winters in the Northern Hemisphere are strictly related to the sun's most active, the highest sunspot year." However, this correlation is only valid in one region in the short term. Extremely cold winters in Central Europe, for example, in many cases coincide with extremely warm winters in the Arctic.
The coldest winters in Tianjin, Shanghai and Hong Kong all occurred in 1957 and 1863, the largest years for sunspots, which seems to support the views of Wakan and Kosiba. But if we follow the trail and go back to the coldest winters and coldest years of the nineteenth and eighteenth centuries, comparing them to the largest sunspot years, we can see that they are not always consistent. In the case of Shanghai, cold years such as 1945 and 1878 are actually seen in the year when sunspots are the smallest. In short, the activity of the sun, such as the number of sunspots, affects the climate on the ground, but its relationship is quite complicated, and so far we have not been able to explore a good law.
<h1 class="pgc-h-arrow-right" data-track="328" > conclusion</h1>
Forty or fifty years ago, most orthodox climatologists in Europe and america believed that climate was stable in historical times. According to the Austrian J. Hann argues that if there is a place that has a thirty-year temperature record or a forty-year rain record, we can set a standard for that place. This standard can represent temperatures and rainfall over the past and centuries to come. This view has been rejected by meteorological data collected by the world in recent decades. In China, ancient writers such as Shen Kuo, author of Mengxi Pen Talk, Zhang Biao, author of Nongdan, and Liu Xianting, author of Guangyang Miscellaneous Records, all doubted the constancy of the climate in historical times; and put forward examples of climate variation in various dynasties, which are recorded in the above books. Chairman Mao said in his article "The Status of the Communist Party of China in the National War": "Our nation has a history of thousands of years, has its characteristics, and has its precious products. For these, we are still elementary school students. Today's China is a development of historical China; we are Marxist historians, and we should not cut off history. "For the history of China's climate development, Chinese literature is a treasure trove, and we should study it well.
The study in this paper is merely a schoolboy's tentative attempt to peek into China's long climate history. In such a vast area as China and in such a long period of five thousand years, it is easy for people to find no clue and get lost in the vast twenty-four histories and more than five thousand Fang Zhi. Therefore, misunderstandings and contradictions are inevitable, especially in the archaeological and phenological periods.
This paper's preliminary study of China's climate history over the past five thousand years can lead to the following preliminary conclusions:
(1) In the first two thousand years of the nearly five thousand years, that is, from the Yangshao culture to the Anyang Yin Ruins, the average annual temperature for most of the time was higher than the current 2 °C. The temperature in January was about 3 to 5°C higher than it is now. The fluctuations between them are currently limited to materials and cannot be explored.
(2) After that, there was a series of up-and-down oscillations, with a minimum temperature of 1000 BC, 400 AD, 1200 and 1700; the oscillation range was 1 to 2 °C.
(3) In each period of 400 to 800 years, a small cycle of 50 to 100 years can be divided, and the temperature range is 0.5 to 1 °C.
(4) Any of the coldest periods in the above cycle seem to start from the east Asian and Pacific coasts, and the cold fluctuations spread westward to the Atlantic coasts of Europe and Africa. There is also a north-to-south trend.
Comparing the fluctuations of China's climate in the historical era with other regions of the world, it can be clearly seen that the fluctuations of the climate are worldwide, although the coldest and warmest years can be in different years, but they are echoed successively. Regarding climate change in European history, the British C. P· E· Brooks was the most accomplished author of the first half of the twentieth century. If we compare his map of temperature rise and fall in Europe since the third century AD with the temperature change map of the same period in China, we can see that there is a connection between the temperature fluctuations between the two places. In the same ups and downs, Europe's fluctuations tend to fall behind China's. For example, the twelfth century was the coldest period in China's modern history, but in Europe, the twelfth century was a warm period; it was not until the thirteenth century that it was cold. Like the cold of the seventeenth century, China also preceded Europe by fifty years. There is a reason why Europe and China are closely related to each other. Because the cold winter in both regions is controlled by the high pressure of Siberia. If the high pressure in Siberia extends eastwards and the northwest winds in northern China are strong, China is cold and Europe is warm. Conversely, if siberian high pressure tends to Europe and Europe has strong northeast winds, northern Europe will be affected and China will be moderate. Only when the Siberian high pressure is sufficient to control all of Eurasia will there be a cold on both sides at the same time.
Norwegian glaciologists have made a map of the rise and fall of the snow line in Norway for nearly 10,000 years based on the results of the rise and fall of the ground. The rise and fall of the snow line is closely related to the temperature of a place. When the climate is warm, the snow line rises, the era turns cold, and the snow line falls. Compared with the snow line in Norway over the past five thousand years, the temperature rise and fall in China is generally the same, but there are differences in succession. The temperature line 0 is the current temperature level, in the Yin, Zhou, Han, and Tang dynasties, the temperature was higher than in modern times; after the Tang Dynasty, the temperature was lower than in modern times. There is also this trend in the Norwegian snow line. But during the Warring States period, in 400 BC, there was a cold period that was not available in China. It should be pointed out that although the height of the snow line is closely related to the temperature, it also depends on the amount of rainfall and the distribution of rainfall seasons, so the curve up and down the snow line cannot be completely represented by the rise and fall of temperature.
Recently, the Institute of Physics of the University of Copenhagen, Denmark, W. Professor Dansgaard, in the glacier block in the Camp Century area of Greenland, studied the temperature when freezing by the radioactive isotopic method, and the result was that when the temperature was high when the ice was high, the isotope increased, and the temperature increased by 1 °C. W. Dansgaard's map of greenland temperature rise and fall over the past 1,700 years is compared with the contemporaneous temperature map of China measured in this article, A represents the fluctuation of China's temperature from the third century to the present. B represents the temperature of Greenland measured with isotopes at the same time. The two lines in the figure can be said to be almost parallel. From the low temperature of the Three Kingdoms to the Six Dynasties period, the high temperature of the Tang Dynasty to the two sudden colds of the Southern Song Dynasty and the early Qing Dynasty, the two places are consistent, but there is a slight difference in time. For example, in the early twelfth century, there was still a high temperature in Greenland, and the severe cold period of the Southern Song Dynasty in China had begun. But the difference is only thirty or forty years, and the temperature in Greenland has rapidly dropped below average. Compared with Europe, the weather in Europe was very warm in the twelfth and third centuries, unlike in China and Greenland. If you go back to three thousand years ago, the cold recorded in the Chinese "Bamboo Book Chronicle" was not found in Europe, and it was not until the Warring States period that Europe cooled down. But in S· G· Johnsen and W. Dansgaard's charts[46] show that there was a cold period of two or three hundred years in Greenland three thousand years ago, echoing the records of the Bamboo Chronicle. Between 2,500 and 2,000 years ago, between the Warring States of China, the Qin and Han Dynasties, Greenland had the same mild climate as China. All this shows that Greenland's ancient climate change is consistent with China, but not from Western Europe. Greenland is more than 20,000 kilometers away from China, and the same climatic changes in ancient times are enough to show that such changes are global. The author believes that this is due to the fact that Greenland and China have different latitudes, but they are on the eastern edge of the continent, and although they face the ocean, they are still continental climates, which are not the same as the oceanic climates of Western Europe affected by atmospheric circulation. The Canadian Geological Survey studied spore pollen left over from ancient soils in eastern Ontario (50°N, 90°W), which resulted in a cold period between 3,000 and 2,500 years ago, but then warmed up similarly to that of China and Greenland. Tu Changwang of China once studied the correlation coefficient between China's temperature and the world's waves at the same time", and concluded that the correlation coefficient between China's winter (December to February) temperature and The North Atlantic wave movement is positive, although the index is not large, in other words, China's winter temperature has a similar change with the winter temperature on the Atlantic coast of North America. In short, the earth's climate changes are controlled by solar radiation, so the cold of the ice age is uniform all over the world. However, small changes in climate, such as changes in annual temperature of 1 to 2 °C, are affected by atmospheric circulation, and the continental climate is different from the ocean climate, which can be affected here.
This paper mainly uses phenological methods to speculate on the change of paleoclimate. Phenology is one of the oldest climate markers; the proportion of sum used to determine the paleo temperature of ancient ice and water was the case in 1947. D. Urry's new discovery, and the results of the two methods are generally consistent, also prove that using phenological materials contained in ancient history books to do paleoclimate research is an effective method. If we can grasp the laws of past climate changes, long-term forecasts of future climates will certainly be complementary. This article is only a preliminary discussion, and there are few problems explained by paleoclimate, but there are many problems caused. If we can take Marxism-Leninism and Mao Zedong Thought as theoretical guidance, implement the principle of "using the ancient for the present", make full use of China's rich ancient phenological and archaeological data, and make periodic long-term forecasts from ancient climate research, as long as we work hard, we can draw results.
<h1 class="pgc-h-arrow-right" data-track="330" > [Description].</h1>
The source of this article is the Journal of Archaeology, No. 1, 1972, Mr. Zhu Kezhen's article "Preliminary Research on Climate Change in China in the Past 5,000 Years", picture source network
<h1 class="pgc-h-arrow-right" data-track="332" > p.s</h1>
Read more: Climate change in other parts of the world
Since 4000 BC, the world's climate has undergone many changes in cold, warm, dry and wet. By analysing historical data from areas with earlier cultural development or more pronounced evidence of climate change, such as the Nile River basin in Egypt, Europe and the Arctic, the world's historical climate change can be divided into the following periods:
(1) Atlantic period (4050 BC - 2650 BC). Also known as climate-appropriate periods. It is warm and rainy, the average temperature is 2.5 °C higher than the modern level, the flood level of the Nile River is 12-20 meters higher than the modern level, and the rainfall in the tropical semi-rainy area is about 3 times that of modern times.
(2) Early Subnational period (2650 BC - 2050 BC). The climate is cold, marked by the freezing of the icy surface of the Arctic Sea, which is about 4 meters below modern level.
(3) Middle Sub-Northern Asia (2050 BC - 1500 BC). The climate warmed, but second only to the Atlantic period.
(4) Late Sub-Northern Period (1500 BC - 750 BC). Cold and dry, the Nordic region experienced continuous severe cold, and the water level of the Nile declined.
(5) The Greek era (750 BC - 150 BC). Warm and humid, northern Europe warmer, the emergence of beech forests, southern Europe is also warmer, the Black Sea level is 3 meters higher than modern.
(6) Roman era (150 BC - 350 AD). Cool and dry, the mountain glaciers once expanded, the Tarim Basin edge and along the ancient Silk Road were richly irrigated by wells and springs, and many prosperous towns appeared.
(7) Late Roman times (350-700). Warm and dry, northern Europe long dry and warm, the southwest of the United States drought, resulting in the drying up of rivers, the Black Sea level is 3 meters lower than modern, the ancient Silk Road declined due to drought, tropical rain and wet.
(8) 8th century (700~800). Northwestern Europe turned colder and tropical rainfall decreased.
(9) Subclimate suitable period (800-1200). It was the warmest period of nearly 2000 years. Northwestern Europe has fewer storms, warm and dry, Mexico is hot and wet, the Nile has increased its flow due to tropical rains, the snow line in the southern Rocky Mountains is about 366 meters higher than it is modern, and the boundary of Arctic drift ice is far northerly than it is in modern times. Around 900 AD, the Eskimos settled in the polar regions.
(10) The Cold Period of the Middle Ages (1200-1450). Northwest Europe is cold and wet, with harsh winters, the surface of the Waters rises by 32 meters, the Americas are cold and dry, the temperature is lower than the multi-year average, and the flood level of the Nile is below the average.
The Warm Period of the Middle Ages (1450-1550). There has been a worldwide sea level rise with abundant equatorial rainfall.
Xiaoice period (1550-1890). The climate has turned cold, polar ice has expanded strongly, mountain glaciers have advanced, alpine snow lines have declined, and ice and snow on land and at sea in most parts of the world have reached their maximum since the end of the last ice age. The climate was the worst in the 17th century, with greatly increasing the number of severe winters and severe colds in Europe, and crop failures caused by wet, low summers. China is also a period of frequent harsh winters.
Further reading: Climate Change in China:
Warm period means that the temperature is above the average, and cold period means that the temperature is below the average (23 °C).
The first warm period: (2000 BC - 1000 BC) Xia, Shang, Western Zhou
The first cold period: the Eastern Zhou
The second warm period: two Han
The second cold period: the Three Kingdoms of Wei and Jin, the Southern and Northern Dynasties
The third warm period: the Tang Dynasty
The third cold period: five dynasties, ten kingdoms and two Song dynasties
The fourth warm period (relatively warm, but not as warm as before): The Ming Dynasty
Fourth cold period: (17th century to 19th century) Qing Dynasty