At a Glance
- A study reveals that the Arabian Desert, now dry, was once home to lakes, rivers, and valleys formed by intense rainfall around 9,000 years ago during the “Green Arabia” phase.
- The research focused on the Rub’ al Khali Desert and found evidence of ancient water-sculpted features, showing how intense rainfall rapidly transformed the landscape during the Holocene Humid Period.
- The African monsoon, which carried moisture from the Asir Mountains, was identified as the source of this rainfall. This indicates a much stronger monsoon than previously believed, influencing the region’s environment.
- This period of increased rainfall created grasslands and savannas, allowing human populations to thrive through hunting, gathering, and pastoral life. Archaeological evidence supports these findings.
- As rainfall declined around 6,000 years ago, the desert began to dry up, highlighting the dynamic nature of climate change and its impact on human adaptation and settlement patterns in Arabia.
A new study reveals that the Arabian Desert, known today for its extreme dryness, was once home to vibrant landscapes shaped by periods of intense rainfall. Researchers from the University of Geneva, King Abdullah University of Science and Technology (KAUST), and Griffith University documented evidence of a massive lake, rivers, and a large valley formed by water, all about 9,000 years ago. This period of increased rainfall, known as the “Green Arabia” phase, occurred between 11,000 and 5,500 years ago and played a crucial role in the region’s landscape and human history.
The team’s study, published in Communications Earth & Environment, focused on the Rub’ al Khali Desert, one of the largest and driest deserts today, where they uncovered ancient water-sculpted features. The research shows that during the Holocene Humid Period, intense rainfall reactivated floodplains, filling a vast depression in the desert. The resulting water overflow eventually carved a deep, 150 km-long valley. These findings challenge the idea that the landscape stabilized slowly after rainfall and instead show that rapid changes occurred in response to the increased precipitation.
The scientists traced the source of this rainfall to the African monsoon, which brought moisture over large distances, including from the Asir Mountains along the Red Sea. Sediment deposits up to 1,100 km from the mountains support this link, indicating that the monsoon was significantly stronger than previously thought. This heavy rainfall likely helped transform the desert into a more hospitable environment, with grasslands and savannas supporting the expansion of human populations. Archaeological evidence in the region shows that people lived and thrived in these wetter conditions, with evidence of hunting, gathering, and pastoral life.
However, around 6,000 years ago, rainfall began to decline, leading to the desert drying up and forcing human populations to adapt once more. The study highlights the dynamic nature of climate and environment in Arabia and provides new insights into how past climatic shifts influenced human settlement and survival in this region. Understanding these ancient climate patterns could help scientists predict future climate impacts in desert regions.
References
- Zaki, A. S., Delaunay, A., Baby, G., Haghipour, N., Blanchet, C., Dallmeyer, A., Sternai, P., Woor, S., Wani, O., Khalil, H., Schuster, M., Petraglia, M., Sylvestre, F., Peyrotty, G., Ali, M., Van Buchem, F., Afifi, A. M., & Castelltort, S. (2025). Monsoonal imprint on late quaternary landscapes of the rub’ al khali desert. Communications Earth & Environment, 6(1), 1–15. https://doi.org/10.1038/s43247-025-02224-1
- Griffith University. (2025, April 4). Ancient lakes and rivers unearthed in Arabia’s vast desert. Phys.Org; Griffith University. https://phys.org/news/2025-04-ancient-lakes-rivers-unearthed-arabia.html
