Changes in weather 700 years ago might have forced Tibetans to reorganize their society, an anthropologist has claimed.
Mark Aldenderfer of the University of Arizona, who is leading a research project in far western Tibet, is quoted by national Geographic as saying in preliminary findings that an abrupt shift in the Asian monsoon caused famine, population movements and political reorganization.
The research project was started last year and will continue with at least two more field seasons.
"Can we learn anything from what they did in 1300 A.D. that would help us understand how people are going to have to deal with any kinds of similar sorts of changes that might take place in the Asian monsoon during the process of global warming?" Aldenderfer asked.
Scientists credit the Asian monsoon with bringing much-needed summer rains to nearly half the world's population.
The seasonal shift in wind usually brings moisture-laden clouds to India, Bangladesh, China, and other countries in south East Asia.
The shift over far western Tibet was probably to a drier phase. Aldenderfer said scientists are still working out the exact nature of the shift—for example, whether bouts of rainfall became harder but shorter, or whether it didn't rain at all.
"All I can say is that overall it became drier in India and Tibet," said another researcher, Carrie Morrill of the National Climatic Data Center in Boulder, Colorado.
Either way, the change would have altered the way springs channel water off the Tibetan plateau, according to Aldenderfer.
Aldenderfer says that his Tibet project is beginning to reveal how the culture high up on the plateau responded. He and his colleagues say they also have some evidence of large-scale abandonment of agricultural fields.
The team will return to Tibet this summer to continue their investigations.
Aldenderfer said intensity is likely to increase and thus cause more erosion.
He believes the Tibetan plateau, like all mountainous areas, is likely to experience earlier snowmelt.
As a result, people who rely on snowmelt for irrigation will be forced to plant their crops earlier, before the start of the traditional growing season.
"Water conflicts are likely to increase in the future as problems of this kind worsen," he noted.