'Ghost towns' are becoming more common in Nepal as parents send their children away to seek better educationGetty

Ethnic Tibetan communities in Nepal's highlands are rapidly shrinking as more parents send their children away for a better education and modern careers, a trend that threatens to create a region of greying ghost towns at the top of the world.

The findings in the study, which was published in the journal Mountain Research and Development, has major social and demographic implications for the Himalayan region.

"Taken together, the outmigration of young people, a low birth rate and population aging raises the spectre of a massive population decline that has already exceeded 30% in the past decade in some communities", said study co-author Professor Sienna Craig, a professor at Dartmouth College.

The study predicts a further population decline of 50% to 60% in the next decade, a trend not likely to be slowed by tourism, niche agriculture or other potential economic opportunities that might prompt the "educational migrants" to return to their native homes.

This is the first documented case where large-scale outmigration is not driven by disease, famine, war, colonial policies, forced assimilation and manual labour markets. Instead, the population decline is driven by parental quest to improve their children's education.

The researchers conducted household demographic and economic surveys in three villages in highland valleys of Nepal along the border of the Tibetan Autonomous Region of China.

The residents, who descend from ethnic Tibetans who migrated from the Tibetan Plateau at least 700 years ago, are subsistence farmers, herders and traders.

The results showed that the religious and secular schools, which now include around 24 monasteries, 15 convents and 35 boarding schools in Kathmandu - as well as other cities in Nepal and India - are seen by ethnic Tibetan highland parents as a way to give their children a "Tibetan" education that leads to social and economic advancement in urban areas abroad.

In the new study, researchers found that nearly 70% of females aged between 15 and 19 live away from their native villages. Among women aged 20 to 29, who are educational migrants, relatively few are married and having children, while many have become nuns.

Speaking to CNN, Namaste Shrestha commented that in his village of Bandipur, a hilltop settlement in Tanahu District, residents were leaving for urban areas via a newly-constructed highway.

"Bandipur became a ghost town. It was going down, and it was very sad for us." he said.

The outmigration stems from the 1960s when China's Cultural Revolution closed Tibet's monasteries where many rural children were educated. The monastery boarding schools reopened in urban areas along with new secular boarding schools operated by the exiles.