Ancient Arabia was once green and lush with rivers, lakes, and grasslands
Arid stretches of sand can hide astonishing secrets. In southern Arabia, experts have uncovered evidence of lush landscapes that existed thousands of years ago.
The team was led by Dr. Abdallah Zaki from the University of Geneva, Switzerland, in collaboration with colleagues from the King Abdullah University of Science and Technology (KAUST) and Griffith University.
Their research revealed prehistoric water pathways, lakes, and a remarkable desert valley, all of which begged a deeper investigation into how storms once shaped this barren region.
Understanding lush, green Arabia – the basics
Thousands of years ago, Arabia looked nothing like the arid, sun-blasted deserts we picture today. Rain fell more often, carving rivers through what is now sand and dust.
Rolling grasslands stretched across the peninsula, dotted with lakes and wetlands where herds of elephants, gazelles, and even hippos roamed. Acacia trees and wildflowers lined the water’s edge, while birds and crocodiles thrived in the marshes.
Nomadic people moved through this green world, hunting game, gathering plants, and settling near freshwater sources. Arabia wasn’t just a pass-through – it was a place people lived, loved, and left their mark on.
You can still see the echoes of this lush past. Rock art in northern Saudi Arabia shows hunters stalking prey and herders leading cattle – scenes impossible in a desert, but common in fertile lands.
Fossils lie buried beneath the dunes, and dry riverbeds, invisible to the naked eye, appear clearly in satellite images.
With this study, Dr. Zaki and his team have uncovered more concrete details about this very different period in time for the Arabian peninsula.
Lakes and wetlands in lush Arabia
Arabia’s Empty Quarter is recognized today for its dunes and scorching heat. Yet traces of freshwater shells, dried-up channels, and lakebeds suggest that parts of this area once sustained diverse aquatic life.
“Based on a series of ages, it appears the lake peaked about 9,000 years ago during a wet Green Arabia period that extended between 11,000 and 5,500 years ago,” stated Dr. Zaki.
Researchers say that rainfall patterns then were strong enough to allow lakes and rivers to form.
Tracing the monsoonal footprints
Scientists used a blend of radiocarbon techniques and analyses of sediment layers to figure out how water shaped the region.
They identified a connection to the African monsoon, which once carried moisture across the Red Sea to Arabia.
This moisture created grassy areas, wetlands, and streams. Cores of lake and river sediments also revealed the fossils of mollusks and confirmed that stable aquatic habitats thrived.
Floods carved in lush Arabia
One of the most striking findings was evidence of a large paleolake measuring about 1,100 square kilometers (425 square miles), and with a depth of roughly 42 yards (38 meters).
“Owing to increased rainfall, the lake eventually breached, causing a great flood and carving out a 93-mile-long valley in the desert floor,” remarked Professor Sébastien Castelltort, who is also from the University of Geneva.
The immense force of the water apparently sliced through sand and bedrock. Satellite images revealed streamlined shapes and steep-sided channels, which indicate heavy flows rather than slow trickles.
Human presence in a changing land
“The formation of lake and riverine landscapes, together with grasslands and savanna conditions, would have led to the expansion of hunting and gathering groups and pastoral populations,” said Professor Michael Petraglia, from Griffith University’s Australian Research Center for Human Evolution.
Archaeological remains in the Empty Quarter support the idea of more habitable surroundings during these lush intervals.
Sites once on the banks of prehistoric lakes show that people took advantage of water-rich environments. Plant and animal resources likely boosted their survival, and encouraged settlements around riverbeds.
The monsoon’s strong effects
The flood features identified in the study highlight periods of unexpected intensity.
Researchers relied on computer modeling to suggest that annual rainfall, at times, rose by as much as 8 to 12 inches (20 to 30 centimeters) above modern levels.
Such moisture allowed rivers to form, drain off the highlands, and feed desert basins.
Evidence shows that these lakes and streams built up enough pressure to erupt through barriers, leading to the carving of deep channels.
Forced migrations out of lush Arabia
The stable, moist climate did not last forever.
“By 6,000 years ago, the Empty Quarter experienced a strong decline in rainfall, which would have created dry, arid conditions, forcing populations to move into more hospitable settings and changing the lifestyle of nomadic populations,” noted Professor Petraglia.
Dryness overtook the dunes, and water sources vanished.
Over time, shifting sands covered much of the evidence of these greener eras, leaving behind faint traces that challenge our assumptions about Arabia’s dry and sandy emptiness.
What does all of this mean?
Although the Holocene humid phase ended millennia ago, today’s scientists hope these findings can spark conversations about desert landscapes around the world.
They show how climate swings can transform lush corridors into barren regions, with vital impacts on human migration.
Researchers also see these remnants as reminders that weather patterns can shift in dramatic ways.
Shallow lakes can vanish, while floods can leave behind spectacular canyons that reshape entire terrains almost overnight.
These newly documented scenes of ancient rivers, lakebeds, and open grasslands in what is today a desert area, urge us to reflect on how drastically climates can vary through time.
The study is published in Communications Earth & Environment.
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