The largest national park in Africa, nestled in the Tassili n'Ajjer plateau of Algeria, houses a unique art museum with over 15,000 paintings and engravings dating back 11,000 years.
These images showcase a vibrant savannah created by elephants, giraffes, rhinos, and aquatic horses, illustrating the environmental conditions of the Sahara, the world's largest hot desert.
During the Green Sahara or North African Humid Period, the Sahara supported lush savannas, numerous rivers, and lakes that now span Libya, Niger, Chad, and Mali.
Scientists have identified periodic greening occurring approximately every 21,000 years over the past eight million years, impacting the distribution and evolution of species, including ancient human migrations beyond Africa.
A team of climate modelers and human scientists developed a climate model focusing on the Sahara, simulating atmospheric circulation and vegetation effects more accurately.
They identified changes in Earth's axial precession, causing the Sahara to green approximately every 21,000 years, bringing warmer conditions and increased rainfall during Northern Hemisphere summers.
Functioning as a gateway, the Sahara regulates species' distribution and evolution between Northern and Sub-Saharan Africa, influencing biodiversity within and beyond the continent.
The model also suggests that the presence of ice sheet blankets on higher latitudes indirectly affected vegetation patterns, potentially hindering species dispersion during the last 800,000 years.
By modeling African humid periods, researchers gained insights into the impact of wet and dry phases on the distribution and development of species within and beyond Africa.
Refined models can help understand how climate warming will affect rainfall and vegetation in the Sahara region and its broader societal implications.
The Tassili n'Ajjer plateau in Algeria hosts Africa's largest national park, featuring an extraordinary art museum with over 15,000 engravings and paintings dating back 11,000 years.
The Sahara, the world's largest hot desert, once supported lush savannas during the Green Sahara, affecting the environment every 21,000 years. This climatic oscillation, known as the Milankovitch cycle, plays a significant role in Sahara's greening, impacting the region's biodiversity and evolution.
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The Sahara Desert, once a green savannah, undergoes transformation every 21,000 years due to Earth's axial progression. This shift, occurring regularly over the past eight million years, has led to increased temperatures and moisture in the air, strengthening the West African monsoon system and shifting the African rainfall belt northward.
This expanded rainfall has facilitated the establishment of savannas and grassy fields across the entire desert.
In Northern Africa, this cyclical wet period aligns with the Milankovitch cycle, known as the precession of the equinoxes, influencing the amount of solar energy received by each hemisphere.
While previous ice ages lacked a humid period, during warmer interglacial periods, the absence of ice sheet blankets on higher latitudes allowed the Sahara to experience prolonged humid intervals, supporting diverse ecosystems.
Understanding historical climate changes in the Sahara is crucial to comprehend the current impacts of anthropogenic climate change. As temperatures rise, the potential strengthening of the monsoon system may have cascading effects on local and global ecosystems.
Sahara's sensitivity and its role as a biogeographic gateway emphasize the Earth's complex response to climate variations, both past and future. –(Greatidea360)
