Denisse Rubio

JuanåÊJosÌ©åÊSanabria

Valeria Cortes

Gabriela Zuluaga

Laura S. Mu̱oz

Scarlett Olivo

Camilo Bohorquez

Abstract:

How has precipitation influenced the environmental change of the Sahara region?

The Sahara used to be a green area with a wide range of vegetation and fauna. Nevertheless, variations in the Earth’s orbit and the tilt of Earth’s axis (It passed from 24.1 degrees to 23.5 degrees [1]) caused severe climate changes that basically meant a shortage of precipitation in the zone. As a consequence, the Atlantic Ocean’s temperature rose gradually and started increasing the regionå«s temperature. The hydrological cycle was then affected, and the Sahara turned into an arid and dry territory. Additionally, there was a complete loss of biomass.

However, since the late 1980s, the environmental conditions started experiencing drastic changes once more; some satellite images have shown how non-fertile and brown soils are acquiring green, shrubby vegetation as a result of increasing precipitation and low temperatures that have begun to be experienced in some places like the Western Sahara. Some nomads from the southwest of Egypt, and North of Sudan åÊsay they have never seen that much rain, nor as many fertile lands as now.[2]

As a matter of fact, there is a theory that states that climatic changes in the Sahara are repetitive rather than continuous. It is supported by some Eolian Sandstones in the Djurab Area [3] that show in their sedimentary structure fossils of vertebrates (from both humid and arid conditions) that alternate within one section and another, and which suggest the continuous changes in the region.

Yet, while the territory turns green again, techniques such as ossification are being implemented in some zones, in order to give back humidity and a wider capacity of absorption of nutrients to the environment. To achieve this goal, it has been crucial to adjust species, and a new water storage system in which water is not lost, but stored. As soon as the cycle reaches the ‰ÛÏgreen stage,‰Û this will not be longer needed.