�����������

A major new study has revealed that one of the driest areas on Earth – the Saharo-Arabian Desert – enjoyed periods of green, humid weather over the last 8 million years.

The findings, which were published in Nature today on Wednesday 9 April, offer a groundbreaking insight into the hydroclimate of this now dry, arid region.

While previous studies suggested that this arid landscape had been in place for at least 11 million years, the new evidence challenges this notion, showing that Arabia was a much wetter place during certain periods in history.

These wetter conditions would have enabled the movement of mammals and other species, which relied on water sources for survival.

The research team includes Huw Groucutt, lecturer in Mediterranean prehistory in the Department of Classics and Archaeology at the University of Malta, who is a corresponding author for the study, as well as Prof. Eleanor Scerri, Affiliated Associate Professor within the same department. The team consists of an international collaboration between the Heritage Commission of the Saudi Ministry of Culture, the Saudi Geological Survey, and various international institutions including the University of Northumbria in the UK, the Max Planck Institute for Chemistry in Germany, and the Australian Research Centre for Human Evolution at Griffith University.

The team travelled to central Arabia in 2019, and collected stalagmites from caves, which have been used to reconstruct a detailed climate record.

The record revealed multiple phases of humid weather in the central Arabian region, suggesting the climate was a lot wetter in the past than it is today.

These episodic humid intervals, which occurred throughout the past 8 million years, were characterised by higher rainfall, which supported a rich diversity of water-dependent fauna.

The researchers believe these conditions were caused by tropical, monsoonal, precipitation from the south reaching further north in the summer seasons.

Lead author , a Royal Society Senior Research Fellow in Northumbria University’s Department of , “Historically, the dry conditions of the Saharo-Arabian Desert have been proposed as a significant barrier to the dispersal of plants, animals, and early humans between Africa and Eurasia, but these findings shed new light on this hitherto unrecognised but important crossroad between Africa and Eurasia.”

“Our findings highlighted that, as the monsoon’s influence weakened over time, precipitation during humid intervals decreased and became more variable.

“This coincided with enhanced polar ice cover over the Northern Hemisphere during the Pleistocene epoch. Our research is one of the longest terrestrial records ever published.”

Faisal al-Jibrin, lead Saudi archaeologist of the Heritage Commission, said “Arabia has traditionally been overlooked in Africa-Eurasia dispersals, but studies like ours increasingly reveal its central place in mammalian and hominin migrations.”

Dr Huw Groucutt of the University of Malta said “we have been working in Saudi Arabia for the last 15 years, seeking to understand long-term human-environment interactions. Previously we had built a record for the last 500,000 years using the remains of ancient, dried-up, lakes, but we knew little of what happened earlier. This eight million year long record illuminates the deep past of the geographical nexus of Africa and Eurasia for the first time”.

The paper Recurrent humid phases in Arabia over the past 8 million years, is now available open access in Nature and provides the most comprehensive record of Arabia's hydroclimate to date, marking a significant step forward in understanding the region's environmental history and its role in shaping past ecosystems.

FURTHER INFORMATION:

The paper was published in Nature on Wednesday 09 April 2025.

Markowska, M., Vonhof, H.B., Groucutt, H.S., Breeze, P.S., Drake, N., Stewart, M., Albert, R., Andrieux, E., Blinkhorn, J., Boivin, N., Budsky, A., Clark-Wilson, R., Fleitmann, D., Gerdes, A., Martin, A.N., Martínez-García, A., Nicholson, S.L., Price, G.J., Scerri, E.M.L., Scholz, D., Vanwezer, N., Weber, M., Alsharekh, A.M., Al Omari, A.A., Al-Mufarreh, Y.S.A., Al-Jibreen, F., Alqahtani, M., Al-Shanti, M., Zalmout, I., Petraglia, M.D., Haug, G.H. (2025). Recurrent humid phases in Arabia over the past 8 million years Nature. DOI:

Images (higher-quality versions available on request from huw.groucutt@um.edu.mt).