Of course this had nothing at all to do with natural climate variability, like when the “wet band” shifted North and South of the equator, making the lands closest to the equator dry (Sahara Desert and The Land of Milk And Honey are pretty parched now when they once were fertile). This MUST be caused by the hand of Man.
The coast of northern Chile and southern Peru has been extreme desert as long as people have lived there, in fact the most extreme desert on earth. Agriculture has never been possible except with irrigation.
The article is pretty incoherent, but it appears the natural ecosystem of trees that held the water and soil from regular flooding got buggered up. Presumably the soil washed away.
I hear that the use of goats has been very hard on the lands of the middle east and north africa. Experiments have been done fencing off areas of scrub land so they cannot be grazed and they have become renewed with vegetation.