The Saudi Heritage Commission has unveiled new evidence of recurrent humid periods that shaped the Arabian Peninsula’s climate over the past 8 million years.
The research, conducted under the Green Arabia Project, is based on one of the longest and most precisely dated cave records ever collected from central Arabia.
Dr. Ajab Alotibi, Director of Antiquities at the Heritage Commission, announced the findings during a press conference held in Riyadh on Wednesday. It is worth noting that the study was published in the science journal Nature.
The study’s findings are based on the analysis of 22 cave formations—scientifically known as speleothems—extracted from seven sinkholes located northeast of Riyadh, near the Shuwayyah area in Rumah Governorate.
Locally, these limestone caves are known as Duhool Al-Summan.
The climate record, preserved in the mineral layers of the stalagmites and stalactites, indicates recurring humid phases over the past eight million years. These wet spells created fertile ecosystems across the Arabian Peninsula, starkly contrasting with today’s harsh desert environment.
According to the study, the Saudi desert—currently one of the world’s largest geographic barriers due to its extreme aridity—once served as a natural corridor for animal and human migrations between Africa, Asia, and Europe.
The researchers found that these ancient wet periods played a crucial role in facilitating the movement of species and early humans across the interconnected continents.
The findings also support earlier fossil evidence from the Arabian Desert that points to the presence of water-dependent species, such as crocodiles, horses, and hippopotamuses.
These animals thrived in riverine and lake-rich environments that no longer exist in the modern desert, highlighting the region’s dramatic environmental transformation.
