WASHINGTON, Nov 22 — Growing frost-resistant crops especially barley enabled humans to establish permanent settlements at high altitudes on the Tibetan Plateau or “roof of the world” about 3,600 years ago, a team of international researchers said.
The researchers from China, Britain and US reported in US journal Science that they studied artefacts, animal bones and plant remains from 53 sites across the northeastern Tibetan Plateau to paint a picture of early human settlement in the region, Xinhua news agency reports.
Despite evidence of an intermittent human presence there dating back to at least 20,000 years ago, the first villages were established only by 5,200 years ago, co-corresponding author Dong Guanghui of China’s Lanzhou University said.
Dong said this is because a long standing tradition of millet farming that had become widely established along the middle and lower reaches of the Yellow River extended upstream into the north-eastern Tibetan Plateau.
But due to the frost sensitivity of millet crops such as foxtail millet and broom-corn millet, the earliest of those settlements were only limited to altitudes less than 2,500 metres.
Barley and wheat — principal cereals of the so-called Fertile Crescent, a region that covered modern day Iraq, Jordan, Syria and Israel — were introduced to this region along with domesticated sheep about 4,000 years ago.
The importation of western cereals, particularly the cold tolerant barley and sheep, enabled humans to adapt to harsher conditions of higher altitudes in the Tibetan Plateau, leading to the establishment of permanent settlements above
3,000 metres about 3,600 years ago.
Interestingly, human expansion into the higher, colder altitudes took place as the world was becoming colder, researchers said.
Dong said as the temperature drops, there may be insufficient food resources, saying “as a result people need to adopt new technologies to increase productivity or some of them move to other sparsely populated areas.”
The study also included researchers from the University of Cambridge, University of Pittsburgh, Washington University in St. Louis, Qinghai Provincial Institute of Cultural Relics and Archaeology, Chinese Academy of Social Sciences and Peking University.