Mother Nature has long been blamed for catastrophes such as massive flooding along China's Yellow River, but new research suggests human activity has been affecting the body of water for almost 3,000 years.
A new study suggests man-made environmental degradation and subsequent flood-mitigation efforts have changed the "River of Sorrow's" flow over the past millennia, a Washington University in St. Louis news release reported.
"Human intervention in the Chinese environment is relatively massive, remarkably early and nowhere more keenly witnessed than in attempts to harness the Yellow River," T.R. Kidder, PhD, lead author of the study and an archaeologist at Washington University, said.
"In some ways, these findings offer a new benchmark for the beginning of the Anthropocene, the epoch in which humans became the most dominant global force in nature," he said.
The findings also suggest the Chinese government's efforts keep the river from flooding have only made things worse. This may have contributed to the devastating floos that is believed to have killed millions of people and led to the collapse of the Western Han Dynasty between the years of A.D. 14 and 17.
"New evidence from China and elsewhere show us that past societies changed environments far more than we've ever suspected," Kidder said. "By 2,000 years ago, people were controlling the Yellow River, or at least thought they were controlling it, and that's the problem."
The researchers looked at ancient sedimentary soils along the river to make their findings. Nearly a third of a 10,000-year cross section was deposited by flooding in only the past 2,000 years. The team determined which sections had been laid down naturally and which had been put there by humans.
The researchers believe the Yellow River was a peaceful body of water until large amounts of farmers started to disturb the ecosystem of the river's Loess Plateau; which consists of some of the world's most "erosion-prone" soils. Around the year 700 B.C officials started to urge people to move into more remote regions of the plateau to make room for larger populations and protect against invaders.
New iron-making technologies increased the effectiveness of plows which exacerbated erosion and deforestation. This sent large quantities of sediment downstream causing deposits to rise above the river's bed and man-made levees. Over thousands of years of human intervention the river's character was dramatically altered.
"Human-caused environmental change is nothing new," Kidder said. "We've been doing this for a very long time, and the magnitude of change is increasing. Unlike ancient China, where human mistakes devastated a single river valley, we now have the technology to make mistakes that can cause devastation on a truly global scale."
