Researchers uncovered evidence that ancient humans survived on the Tibetan Plateau during the coldest period of the past 2.5 million years, demonstrating their resilience and adaptability. In 2019, Wenli Li of the University of Chinese Academy of Sciences in Beijing and her team discovered a site on the southern Tibetan Plateau in the Yarlung Tsangpo River Valley, located 3,800 meters above sea level, where numerous artifacts indicating human habitation were found.
They named the site Pengbuwuqing after a nearby hill. Radiocarbon dating of ancient bones and charcoal from the site revealed three distinct periods of human occupation between 29,200 and 23,100 years ago. Two of these periods, around 25,000 and 23,000 years ago, coincide with the Last Glacial Maximum.
The Last Glacial Maximum, which lasted from 26,500 to 19,000 years ago, was the most severe phase of the Late Pleistocene ice age, a time when most of the Earth's surface was covered in ice. Global temperatures during the Last Glacial Maximum remained approximately 4 degrees Celsius to 5 degrees Celsius lower than today's average, according to the New Scientist. Massive ice sheets and polar ice caps covered large portions of the Earth, making survival difficult for humans.
"The Tibetan Plateau was previously thought to be uninhabitable during the last glacial maximum," said Li. Evidence found in the region shows that humans lived on the Tibetan Plateau before and after the Last Glacial Maximum, but no signs of occupation during this period had been found until now.
"No archaeological site had previously been dated to this period," stated Feng He of the University of Wisconsin-Madison, who was not involved in the study. Previous research had proposed that river valleys on the southern Tibetan Plateau may have served as refuges for Tibetans escaping the intensifying cold of the Last Glacial Maximum, according to He. "It's satisfying to see that this discovery supports that hypothesis," he added.
At the site, the researchers found stone tools and the first ochre pieces ever discovered in Tibet. Ochre is a red-colored rock used in ancient art. Stone tools found at the site resemble those from older sites farther north in the plateau's interior.
To better understand the environment during these occupations, researchers analyzed nearby stalagmites and lake cores, which provide climate data through their chemical composition. The findings suggest that the river valley had more moisture than expected for the harshly dry ice age in Tibet. The increased moisture allowed cold-tolerant plants and herbivores to persist in the river valley.
Li explained that as the climate became colder and drier, people migrated into the river valley. "The valley likely provided essential resources—water, vegetation, and game needed for survival," she said.
During the Last Glaciation, extreme cold, sparse vegetation, and low oxygen levels at high altitudes made survival difficult on the Tibetan Plateau.
"This discovery reinforces the idea that early humans were highly resilient and adaptable to extreme conditions," He stated. Li and her team plan to further investigate how climatic shifts during the Last Glacial Maximum influenced human occupation and migration at the site.
The article was written with the assistance of a news analysis system.
