Desertification land in the source region of the Yellow River increased from 1975 to 2005, mainly in the west, north, and south areas. The total desertification land grew from 19,297.34 km2 to 22,042.32 km2, with severe, moderate, and light desertification all increasing. 57.28% of the desertification land in 2005 came from non-desertified land in 1975, while the rest developed from lower degrees of desertification. Climate change and overgrazing were the main factors causing this increase, with rising temperatures being the main natural factor.