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Much of the Sahara was green grassland dotted with lakes as recently as 6,000 years ago, watered by stronger monsoon rains.

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Scientists call this era the African Humid Period. It began about 14,500 years ago and ended in stages between about 6,000 and 5,000 years ago. The cause was precession, a slow wobble of Earth's axis that shifts which season falls when the planet is closest to the Sun; it brought stronger summer sunshine to North Africa and pushed the monsoon rains far north. Lake Megachad, in today's Chad, grew to about 1,000 by 600 kilometres, then the largest lake on Earth. People herded cattle across the region and painted what they saw: the Cave of Swimmers in Egypt's Gilf Kebir shows figures that appear to be swimming, in what is now one of the driest deserts on Earth.

Türkçe oku
Sahra'nın büyük bölümü, bundan yalnızca 6.000 yıl önce, güçlü muson yağmurlarıyla beslenen, göllerle bezeli yeşil bir savandı.

Bilim insanları bu döneme Afrika Nemli Dönemi der. Dönem yaklaşık 14.500 yıl önce başladı ve 6.000 ile 5.000 yıl önce arasında aşama aşama sona erdi. Nedeni presesyondu: Dünya ekseninin yavaş yalpalaması, gezegenin Güneş'e en yakın olduğu zamanın hangi mevsime denk geldiğini değiştirir. Bu değişim Kuzey Afrika'ya daha güçlü bir yaz güneşi getirdi ve muson yağmurlarını çok daha kuzeye taşıdı. Bugünkü Çad'daki Megaçad Gölü 1.000'e 600 kilometreye ulaştı ve o dönem dünyanın en büyük gölü oldu. İnsanlar bölgede sığır sürüleri güttü ve gördüklerini kayalara resmetti: Mısır'daki Gilf Kebir'de bulunan Yüzücüler Mağarası'nda, bugün dünyanın en kurak çöllerinden birinin ortasında, yüzüyormuş gibi görünen insan figürleri vardır.

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Background reading: African humid period
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