HUMID PHASES ONCE TURNED ARABIAN DESERT INTO A LUSH PARADISE: STUDY

Mineral deposits, speleothems, and archaeological sites reveal a lush history for the Arabian Peninsula, challenging theories of human migration

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The region called Arabia sits at the heart of the earth’s driest deserts, stretching from the Sahara in the west to India’s Thar Desert in the east. It holds the distinction of being the largest biogeographical barrier on the planet. Over millennia, the arid conditions of the Saharo-Arabian Desert are expected to have prevented hominins and wildlife from migrating between Africa and Eurasia.

Research has found that this arid barrier has existed for at least 11 million years.

Then again, fossil evidence from the late Miocene and the Pleistocene epochs has suggested that water-dependent animals like crocodiles, hippopotamuses, and horses roamed the region as recently as 74,000 years ago.

The two facts raise a curious idea: could Arabia, the formidable wall of dryness, have once been a more nourishing land?

How donkeys digging wells help life thrive in the desert

Mineral deposits uncovered recently in the caves of central Saudi Arabia have bolstered this possibility: that Arabia was indeed once part of a lush green landscape that, among other things, allowed animals — including our ancestors — to migrate through as they spread out of Africa.

According to the researchers who studied the deposits, the cause of this lushness was intermittent phases of humidity the region experienced in the last eight million years, which gradually turned a desiccated landscape into a well-watered grassland. Their findings were recently published in Nature.

In search of Green Arabia