What is the difference between desertification and accelerated desertification?

Desertification, in principle, is a natural process by which formerly productive land becomes a desert as a result of climatic change or prolonged drought. Accelerated desertification is a type of land degradation that occurs in arid and semi-arid areas and is brought on by human activities. This term generally is used to describe a loss of more than 10% productivity as a consequence of erosion, soil compaction, forest removal, overgrazing, drought, salinization, climate change, depletion of water sources, and other factors.