The contradiction of ethnic invasion in the ancient history of China mainly came from the desert in the north. Because ancient China was a mainland country, there were oceans in the east and south, which was basically an obstacle for human beings to explore the world. There is a tall Qinghai-Tibet Plateau and a vast desert in the west. Due to the terrain and climate, it is impossible for foreigners to suddenly attack the Han regime in the east. Therefore, the Han regime has been under pressure from the north in ancient times, such as Xiongnu, Turkic, Qidan, Jurchen, Mongolia, Manchu and so on.
Because the northern minority areas are nomadic economies, they rely entirely on grasslands to support themselves. When the climate gets cold, the grassland grows badly and can't get enough food supply. At this time, they will attack the Han regime in the south to get food. At this time, the south is also getting cold, and food and other materials will be greatly reduced, thus reducing the overall national strength. Therefore, the frequent foreign invasions in the north are actually caused by the survival pressure in the cold climate. Therefore, in the cold climate period, the Central Plains Dynasty will face the dilemma of internal troubles and foreign invasion.
A new research result of Institute of Earth Environment of Chinese Academy of Sciences shows that the climate change in recent 2000 years has a corresponding relationship with the rise and fall of some dynasties in the history of China, and the collapse of most dynasties occurred in the low temperature range where the climate became colder.
This research is supported by the National Natural Science Foundation of China and the Ministry of Science and Technology, and related papers have been published in the authoritative academic journal China Science.
According to Liu Yu, a research leader and researcher at the Institute of Earth Environment, Chinese Academy of Sciences, the researchers have successfully constructed a temperature change curve from 484 BC to 2000 AD, which can represent a total of 2,485 years in central and eastern China, by studying the annual rings of Sabina przewalskii, a unique tree species in China, Qinghai-Tibet Plateau, and connecting them with the annual rings of Sabina przewalskii unearthed from the Tang tomb. This is also the longest tree ring reconstruction temperature series in Asia.
By analyzing the temperature curve of tree ring reconstruction, researchers found that the collapse of dynasties in China history almost corresponded to the low temperature range on the curve, and the extinction years of Qin Dynasty, Three Kingdoms, Tang Dynasty, Song Dynasty (North and South Song Dynasty), Yuan Dynasty, Ming Dynasty and Qing Dynasty were all below the average temperature in the past 2485 or extremely cold.
The temperature curve of tree ring reconstruction also shows that 907, when the Tang Dynasty perished, was also a low temperature period compared with the warm period before and after it. The cold period is from 127 1 to 1296, and the average temperature in 26 years is 1.82 degrees Celsius, which corresponds to the demise of the Song Dynasty and the establishment of the Yuan Dynasty. 1599 to 1702 was also a long cold area, and the average temperature in this period was 1.77 degrees Celsius, which was the period of the demise of the Ming Dynasty and the establishment of the Qing Dynasty.
"Although in the past two thousand years, the collapse of most dynasties in China and the corresponding phenomenon of low temperature range are not accidental coincidences, we cannot assert that the rise and fall of dynasties are entirely caused by climate change." In an interview with Xinhua News Agency, Liu Yu believes that there are many reasons that affect the historical process, and climate is only one of them. Due to the political corruption of the feudal dynasty itself, coupled with the poor harvest and hunger caused by low temperature, it may eventually lead to peasant uprisings and wars, leading to the change of dynasties. In addition, in the cold period, the southward migration of grassland pasture will also lead to the invasion and southward migration of northern nomads.
Through research, researchers also found that global warming, which people are generally concerned about at present, may not be the warmest period in history. In the past 2485 years, the temperature in four historical periods was higher than or close to the average temperature from 1970 to 2000.
Among them, the period from 40 1 to 4 13 is the warmest period in recent 2485. During 348-4 13, the temperature changed suddenly, from extremely cold to extremely warm, and then cooled rapidly. Because this period was in the Eastern Jin Dynasty in China, researchers called this sudden change of temperature "Eastern Jin Event".
At present, researchers in China are further studying the mechanism of the "Eastern Jin Incident". This is of great significance for understanding the past climate change, revealing the law of climate change and predicting the future climate development trend.
The natural environment is the earth space on which human beings live. In the long historical period of human society, the natural environment is always in constant movement and change. Every major change in the natural environment in time and space has brought great influence to human society. On the contrary, human activities also affect and change the surrounding natural environment. Understand the general trend of global climate change in the past 5000 years and the relationship between global climate change and human activities. How has the climate and environment in East Asia changed in the past 5,000 years? Is there a corresponding relationship with the important events and social and cultural patterns in China's history?
Second, climate change and dynasty change since 5000:
According to relevant data, since 1 10,000 years ago, glaciers have melted a lot and the climate has obviously warmed up. Since 4,000 years, the climate in China has experienced several fluctuations in temperature. Yin-Shang period was the last period of Holocene warm and wet period, and the general climate trend was cold and dry after that.
From 3000 BC to 1000 BC, the banks of the Yellow River were covered with bamboos. This is the first warm period in the history of China civilization. Yao, Shun, Yu, Xia, Shang and Western Zhou Dynasties are also the cornerstones of Chinese civilization.
Confucianism admired and envied Xia, Shang and Zhou Dynasties. The historical temperature change map drawn by the famous meteorologist Zhu Kezhen shows that the temperature of the three generations is higher than that of the Han and Tang Dynasties, and the development of civilization is also higher than that of the Han and Tang Dynasties.
From about 1000 BC to 850 BC, the temperature began to drop. According to historical records, in the seventh year of the Zhou Dynasty (903 BC), "Li Wangsheng was born, the winter rain and hail killed cattle and horses, and the rivers and rivers were frozen", and the crops were seriously damaged. The economy of the Zhou Dynasty began to languish and the national strength declined.
The period from 770 BC to 476 BC was the second warm period in the history of Chinese civilization. According to ancient books such as Zuo Zhuan and The Book of Songs, there was often no ice in winter in Shandong at that time, but it could be harvested twice a year in Qilu area, and subtropical plants such as bamboo and plum trees were more common.
From 476 BC to 100 BC, from the early Warring States period to the Western Han Dynasty, the Norwegian snow line showed that the world temperature dropped sharply, which was clearly recorded on the climate change map of Zhu Kezhen.
From early AD to AD 600, the climate became cold again, and the average temperature was about l℃ lower than that in modern times. This is also the second great division in China's history.
In the third year of Wang Mang's windy days (AD 16), "February is easy, and earthquakes, heavy rains and snows, especially in Kanto, are ten feet deep and bamboo and cypresses are withered; In August of the fourth year of Wang Mang's windy weather, hundreds of officials and horses froze to death. "
In the early Eastern Han Dynasty, the cooling began to weaken, but during the period from 180 to 600 years, that is, in the late Eastern Han Dynasty, the cold became worse. Han Dynasty "In the sixth year of Emperor Guang He of Lingdi (183), the winter was extremely cold, and the ice thickness of Beihai, Donglai and Wolf Evil Wells was over one foot." This fluctuation was a prelude to the great climate cooling in Wei and Jin Dynasties, from which a cold climate period of about 400 years began.
During this period, Zhang Jiao founded Taiping Road and launched the Yellow Scarf Army Uprising in A.D. 184, which led to the demise of the Eastern Han Dynasty and the formation of the later Three Kingdoms, the Jin Dynasty and the Southern and Northern Dynasties, which lasted for more than 400 years, causing serious economic and cultural destruction and people's suffering.
The period from 600 to 1 100 was the third warm period in the history of China. In Chang 'an in the Tang Dynasty, there was no ice and snow for several winters, and plum blossoms and oranges could be planted. The taste of fruit was the same as that of Sichuan. The warm climate is conducive to the development of agriculture, and the national strength of the Tang Dynasty gradually became stronger.
But from 80 1 to 960, the climate turned cold. In the eighteenth year of Zhenyuan, it snowed frequently in the winter solstice in southern Henan. In the eighth year of Yuanhe, there was a great cold in the East. Until the Five Dynasties and Ten Kingdoms, the country was in a period of turmoil.
After the second year of Emperor Taizong of the Northern Song Dynasty (AD 985), the climate suddenly turned cold, and the strange cold scene covered with snow and ice reappeared in Jianghuai area. After the Tang Dynasty, all the fruit trees that could be planted in Chang 'an and Luoyang froze to death, and the Huaihe River basin, the lower reaches of the Yangtze River and Taihu Lake were frozen and opened to traffic.
The severe drought and flood in the first half of the Qing Dynasty was one of the reasons for the San Francisco rebellion in the early Qing Dynasty. At the end of the Qing Dynasty, the political situation had turned from prosperity to decline, and the chaos of the Nian Army, the Taiping Heavenly Kingdom and the Hui uprising were everywhere, and the Qing Dynasty soon came to an end.
The occasional cold and drought in the history of China resulted in insufficient accumulated land temperature, impaired crop growth and serious crop failure. China has always been an agricultural country in ancient times, and severe famine will inevitably lead to turmoil, which will further affect the evolution of political, military, economic, social, cultural and material civilizations in various dynasties.