51¶¯Âþ

A DRAMATIC global shift in the world’s climate may have turned an area
covered with rivers and lakes into one of the driest places on Earth. 51¶¯Âþs
were convinced the Atacama Desert in western South America formed more than 10
million years ago when the Andes grew high enough to keep moist air out. But a
new study led by geologist Adrian Hartley of the University of Aberdeen is
challenging this interpretation. He says the Atacama region actually stayed wet
until around 3 million years ago (Geology, vol 30, p 43). This is when
the African deserts formed, which suggests that the southern
hemisphere—and possibly the entire globe—fell victim to the climate
change that created these great deserts.