Miracle in the Sahara: Oasis Sediments Archive Dramatic History
22/05/2013 Deja un comentario
(…..) Dreams of a GREEN Sahara. Kröpelin is fascinated by relationships among the histories of the climate, the earth and mankind. He is interested in how people responded to change in Sahara. Here in the inhospitable dryness of the desert, blades and arrowheads made of quartzite, the ring-shaped traces of settlements are evidence Homo Sapiens were once omnipresent in the Sahara. “A Stone-Age burial mound,” Stefan Kröpelin says, pointing to one of the piles of stones rising from plain. “What’s so fascinating about it is that everything is well preserved in just the way it was left thousands of years ago”. During an expedition into the no-man’s land east of the Ounianga lakes, Kröpelin even believes he found traces of an ancient Egyptian caravan. He discovered a stone statue of a man, visible from far away on a high plateau, similar to the statues uses on mountains today as guideposts for the hikers. Kröpelin suspects what he had found was a landmark for desert travelers from days of the pharaohs. There is evidence that the expeditions from the ancient Egypt extended to at least the current Egyptian-Libyan border, says the geologist. Few years ago, hieroglyphics were found there, at Uwaynat Mountain. Kröpelin thinks it is conceivable that traders stopped there to replenish their water supplies before continuing their travels toward Ounianga. To reinforce his theory, he points to eroded cliffs that shape the landscape along the shores of the Ounianga lakes. Over the millennia, the constant wind has carved them into step pyramids. Kröpelin believes that the similarity between this shape and that of structures along Nile is more than coincidental. Theorizes gradual desertification drove Egyptian people out of their original habitat, which is now the Sahara Desert. He points out that silhouettes of the tombs of the pharaohs, visible from a great distance, are characteristic of precisely the region that was once home to the Egyptians. Will a return ever be possible? Will the Sahara turn green again one day? Even Kröpelin knows that by answering these questions he is delving into the realm of speculation. Nevertheless, he is gathering evidence. Rare rainfall over otherwise dry Sudan in 1988 awakened his suspicions for the first time. If everyone was talking about climate change, why shouldn’t the monsoon in Africa be changing, too? Perhaps global warming could drive it back to the state it was in once before, after the ice age. Since that rainstorm in Sudan, Kröpelin has been recording all signs of climate change during his trips, looking for answers to questions like: Where is camel grass growing more abundantly than in previous years? How productive are the few watering holes? And what are the camel herders and date farmers saying? Of course, all of this is merely anecdotal evidence that doesn’t stand up to scientific scrutiny. Nevertheless, Kröpelin is convinced the evidence is growing. In fact, he says, he even believes there is now real evidence of change, and that the desert is getting greener. The geologist feels validated by recent news from Faya oasis. Last summer, the residents told him, they were surprised by a sudden downpour. Huts were washed away and people drowned. This had never happened before, they said.