The desert in northern China shrank greatly compared with the last glacial maximum from 26000 to 16000 years ago, and expanded obviously compared with the holocene warm period from 900 to 5000 years ago. 
The Sahara Desert is located on both sides of the tropic of Cancer, controlled by the subtropical high pressure zone, and has a hot and dry climate
 the researchers believe that the climate change, and even the ice amount change in the high latitudes of the northern hemisphere, are the main factors affecting the surface environment changes of deserts and sandy lands in China.