There is also some good footage of the camel caravan I rode out into the dunes when I was in Dunhuang last fall.
They talk about having to relocate entire cities to escape the advancing dunes. This is not at all unusual in the history of this region, or of the the Taklamakan Desert Basin. These dunes travel. Entire civilizations have been lost to them. It's no surprise that they might do that again.
Dunhuang is truly an oasis town. The dunes tower around it, and the city abruptly ends at the end of the street when it hits sand: