New Evidence Suggests That the Sahara Desert Used to be Tropical
New research suggests that the Sahara desert used to be moist and green before it has turned into one of the largest deserts on Earth. An analysis and simulation of weather patterns has indicated that a majority of the Sahara desert has experienced very heavy and continuous rains more than a thousand years ago.
A study by Robert Korty and William Boos, professors from Yale University, has indicated that changes in the weather patterns in the region have turned the Sahara into what it is now. Their research has focused on the weather patterns from the Holocene era and it is through their computer simulations that the "Intertropical Convergence Zone" is not in the same place as it is today.
They have discovered that an atmospheric circulation known as the Hadley circulation has travelled too far up the equator during this time which has called severe storms and hurricanes in the area. An unusual shift in weather patterns, it has been known to bring about heavy rains in places that used to be quite dry.
Now it has descended downward to a place nearer the equator and has been sucking in humidity. Interestingly, where the Hadley circulation descends is where the temperatures are quite arid and the air very dry creating desert like conditions in sub-tropical regions like the Sahara as explained by the College of Earth and Mineral Sciences in Pennsylvania State University.
This finding can also be supported by archaeological finds that ancient fishing gear has been found underneath many of the uninhabitable places in the Sahara. There are also a number of fossil records that indicate that there have been fishes and other aquatic creatures that lived during this "Green Sahara" of the ancient.
A study from Cambridge and the University of London has found that the Sahara used to be covered by a dense river network which was divided into multiple branches. This condition has allowed the migration and movement of a number of aquatic species from neighboring areas into many of the oases found in the region.