Environment in southwest China 'overwhelmingly' shaped by human activity for more than 1,800 years
Human activity has had an "overwhelmingly" destructive effect on the natural environment in the region between Vietnam and the Tibetan plateau since the late Han Dynasty nearly two thousand years ago, according to a new study by Chinese scientists.
Analysing sedimentary records from the Red River, which originates on the southeast Tibetan plateau and enters the South China Sea near Hanoi, the scientists found traces of aggressive human activities, such as the massive destruction of forests, farming, and mining, starting as early as 1,800 years ago.
The start of environmental destruction in Vietnam occurred within the Second Chinese Domination period in Vietnamese history from AD43 to 544 .
After conquering most parts of Vietnam and naming it Jiaozhi province, the Eastern Han Dynasty maintained a strong military presence in the region, constructing a number of settlements to suppress local resistance.
Before AD220, the landscape of the region was predominantly shaped by natural elements such as rain and wind, according to sedimentary records, which were obtained near the mouth of Red River in the South China Sea.
But around that time, which marked the end of the Han Dynasty, “enhanced human activity overwhelmed the natural climatic controls on erosion in the Red River,” the researchers said in the paper.
The finding would shed new light on the history of southwest China, Vietnam and the origin of Tibetan culture.
It was commonly believed that until AD600, the Red River region was only populated by some small tribes with primitive civilization who were unlikely to cause as much damage to the natural environment as the Han Chinese populations with more advanced economy and technology inland.
The study, led by researchers with the Chinese Academy of Sciences’ key laboratory of marine geology and environment in Qingdao, Shandong, was published on the latest issue of international journal Geology last week.
Shi Shuo, professor of Tibetan history in Sichuan University, said it would be interesting to couple the scientific findings with historical records to study the early history of southwest China and its surround regions.
“It was a time before Tibet was settled. The area was roamed by many tribes that were constantly on the move and at war with one another,” he said.
Most first-hand information about these tribes has been lost. Historians mainly rely on indirect descriptions about them from Chinese documents, which were often biased and vague due to the long conflict between these tribes and the Han population.
But Shi cautioned that the sedimentary record had its limits.
Because the trace elements in sediment could not tell precisely where the human-induced erosion took place, it would be difficult to link the environmental destruction to specific populations or historical events.