Climate disasters caused societal upheaval 3,000 years ago in China, study of 'oracle bones' hints

Abrupt population drops over 3,000 years ago in the waning years of China's Shang dynasty were likely the result of a deadly increase in typhoons and related weather events, according to a new study that combined ancient texts, archaeological evidence and paleoclimate modeling.

These coastal typhoons likely caused disastrous climate events, such as massive floods, that hit China's Central Plains, sometimes called the "cradle of Chinese civilization." This area was home to a royal dynasty called the Shang that ruled the Yellow River valley from 1600 to 1046 B.C. The Shang dynasty is known for having the earliest evidence of writing, in the form of divination texts inscribed on "oracle bones" made from turtle shells and ox shoulder bones. In addition, tens of thousands of bronze, ceramic and jade artifacts have been unearthed at the Shang capital in the modern-day city of Anyang, revealing the wealth and power of the dynasty before it was overthrown by the Zhou people.

In a study published Wednesday (March 4) in the journal Science Advances, researchers investigated whether extreme climate events could have contributed to cultural changes in inland China around the time the Shang dynasty collapsed. The researchers correlated information from oracle bones and archaeological sites with paleoclimate models and discovered that intensified typhoons and related weather events might have been to blame.

First, the team counted the instances of weather-related writing on over 55,000 pieces of oracle bone scripts dated to between 1250 and 1046 B.C., the last two centuries of the Shang dynasty. The oracle bones included a larger proportion of divinations related to upcoming heavy rain and water-related disasters in the middle of the time period, suggesting an increase in the Shang society's concern about extreme rainfall events in the Central Plains, the researchers wrote in the study.

The Shang dynasty was not the only society experiencing a population decline in what is now central China. The team examined archaeological data for flood layers in the Chengdu Plain southwest of the Central Plains. Chengdu was occupied by the Shu kingdom, which existed at the same time as the Shang but lasted until 316 B.C. They found evidence of flood-damaged buildings dating to 950 B.C. and flood-destroyed dikes from 500 B.C. Additionally, archaeological sites in the Chengdu Plain decreased in number and became geographically concentrated in relatively elevated areas, suggesting that people were relocating to higher ground.

The researchers' paleoclimate modeling showed that northward typhoons and related weather events intensified between 1850 and 1350 B.C., affecting the Shang in the Central Plains, and that westward typhoon activities intensified between 850 and 500 B.C., affecting the Shu in the Chengdu Plain.

"What stood out here was intensified typhoon activities," the researchers wrote, which may have caused widespread inland flooding and resulted in population decline and social changes in the Central Plains and Chengdu Plain. "Intensified typhoon activities exerted unexpected disastrous influences in inland China during the Bronze Age," they wrote.

The climate conditions in this area were extremely variable, however, and the researchers noted that other climate-related hazards may have contributed to cultural instability in Bronze Age China. In particular, droughts caused by El Niño-like conditions could have hit the Central Plains around 1350 B.C. and disrupted the culture, similar to how protracted droughts ushered in the collapse of many cities within the Maya civilization.

Although the researchers are not certain exactly how the ancient climate affected inland Chinese civilizations, they suggested that typhoon-induced extreme weather events were as much of a concern in the past as they are today. But by integrating archaeological evidence, oracle bone scripts and paleoclimate proxies, the researchers wrote, the study is the first to reveal links between coastal typhoon activity, inland extreme rainfall, flooding and social changes around 1050 B.C.

Live Science reached out to the study's authors for comment, but they did not respond by the time of publication.