A groundbreaking discovery has revealed that ancient humans braved the unforgiving conditions of the Tibetan Plateau—the highest and one of the harshest landscapes on Earth—during the coldest period of the past 2.5 million years. The findings challenge previous assumptions that the region was uninhabitable during the last glacial maximum, demonstrating the extraordinary adaptability of early humans.
The last glacial maximum, spanning from 26,500 to 19,000 years ago, was the most severe phase of the Late Pleistocene ice age. Vast ice sheets blanketed significant portions of the Earth, while global temperatures were an estimated 4 to 5 degrees Celsius lower than today’s average, according to a report by New Scientist.
“The Tibetan Plateau was previously thought to be uninhabitable during the last glacial maximum,” said Wenli Li of the University of Chinese Academy of Sciences in Beijing. “Extreme cold, sparse vegetation and low oxygen levels at high altitudes made survival incredibly difficult.”
While archaeological evidence had confirmed human presence on the plateau before and after this Ice Age period, no signs of occupation during the peak of the glaciation had been found—until now.
Breakthrough discovery at high altitude
In 2019, Li and her team made a significant discovery in the Yarlung Tsangpo River valley on the southern Tibetan Plateau, at an altitude of 3,800 meters above sea level. The site yielded a trove of artifacts indicating human habitation.
The researchers unearthed 427 artifacts, including stone tools and the first pieces of ochre—the red pigment often used in ancient art—ever found in Tibet. Radiocarbon dating of ancient bones and charcoal at the site identified three separate periods of human occupation between 29,200 and 23,100 years ago. Remarkably, two of these periods, around 25,000 and 23,000 years ago, coincide with the last glacial maximum.
“No archaeological site had previously been dated to this period,” said Feng He of the University of Wisconsin-Madison, who was not involved in the study. “This discovery reinforces the idea that early humans were highly resilient and adaptable to extreme conditions.”
How did they survive?
To better understand the environment at the time, researchers analyzed nearby stalagmites and lake sediment cores, which hold chemical records of past climates. Their findings suggest that the Yarlung Tsangpo River valley had more moisture than expected, supporting cold-resistant vegetation and herbivores—essential resources for survival.
“The valley likely provided essential resources—water, vegetation, and game needed for survival,” Li explained.
Stone tools recovered from the site resemble those from older sites farther north in the plateau’s interior. This similarity suggests that as the climate grew colder and drier, people may have migrated into the river valley in search of more hospitable conditions, Li added.
Previous research had theorized that river valleys on the southern Tibetan Plateau could have served as sanctuaries for early humans escaping the intensifying cold of the last glacial maximum. The new findings strongly support this hypothesis, he noted.
“It’s satisfying to see that this discovery supports that hypothesis,” he said.
Looking ahead, Li and her team plan to further investigate how climatic shifts during the last glacial maximum influenced human occupation and migration in the region.
The newly discovered site has been named Pengbuwuqing, after a nearby hill, and could hold further clues about humanity’s remarkable survival against the odds in one of the most extreme environments on Earth.