With more rain, the region gets more greenery and rivers and lakes. At repeated intervals throughout Earth’s history, there’s been more energy pouring in from the sun during the West African monsoon season, and during those times-known as African Humid Periods-much more rain comes down over north Africa. These fluctuations are caused by slight wobbles in the tilt of the Earth’s orbital axis, which in turn changes the angle at which solar radiation penetrates the atmosphere. The Sahara has long been subject to periodic bouts of humidity and aridity. In a new study in the journal Frontiers in Earth Science, Wright set out to argue that humans could be the answer to a question that has plagued archaeologists and paleoecologists for years. So where did all that water go?Īrchaeologist David Wright has an idea: Maybe humans and their goats tipped the balance, kick-starting this dramatic ecological transformation. The now-dessicated northern strip of Africa was once green and alive, pocked with lakes, rivers, grasslands and even forests.
But 11,000 years ago, what we know today as the world’s largest hot desert would’ve been unrecognizable. When most people imagine an archetypal desert landscape-with its relentless sun, rippling sand and hidden oases-they often picture the Sahara.
0 kommentar(er)
