Why did the Sahara turn into a desert?

Question

Why does fertile land turn into sand and how exactly did this fertile land form in the first place?

In: 10

Answer 1

over grazing –

first over graze with cattle, then when there is not enough pasture for cattle, bring in sheep after sheep bring in goats.

goats are really good at creating deserts (cows and sheep nibble goats will eat the roots of plants)

also using fire to clear land is another great way to create deserts