How and why was the Sahara desert?



5000 years ago the world's most famous desert — the Sahara, which has stretched its sands in northern Africa, is a green area full of lakes, hippos and giraffes. What is so greatly changed the character of the region?

Thanks to a recent study scientists have found out that climate change has occurred throughout almost the entire northern part of the continent.
To understand the reason for such drastic changes, the researchers needed to analyze the composition of the dust that has fallen into the waters of the Atlantic Ocean from the west coast of Africa. Scientists studied the sand on the coast, as well as the land from the ocean floor, they specifically raised by the drilling vessel. By the way, the age of the analyzed sand is 30,000 years old — it is clear that this sand has gone through a lot in his lifetime, and its study may give researchers more. Exploring the mud at the bottom of the sea, scientists can determine the change in the amount of sand in a given time period. Thus, we can figure out how to change the climate of Africa. In simple words, a lot of sand — dry climate, a little sand — more humid air, and therefore, the mild climate.

Period humid climate in this part of Africa began and ended quickly. This fact is confirmed by previous studies of sand carried by other scientists. However, by the end of the wet period, that is about 6,000 years ago, the sand in North Africa was 5 times less than it is now — far less than scientists previously assumed.

This research will allow scientists to better understand the relationship between the amount of sand and climate of Africa, explained study leader paleoclimatologist David McGee. He added that as a result be able to trace exactly what the climate in Africa was in a given period of time. Sand from the Sahara Desert is a large part of the sea of mud on the African coast. Moreover, the sand is constantly "travels" and may even reach the shores of North America.

Currently, McGee and his colleagues are trying to determine whether the analysis of sand will help solve a long-standing problem: why in North Africa can not return humid climate that prevailed there 6,000 years ago.

See also: The Mysterious Antarctica, where there are mammoths.

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