Fossil coral records provide new evidence that frequent winter shamals, or dust storms, and a prolonged cold winter season contributed to the collapse of the ancient Akkadian Empire in Mesopotamia.
Past studies have shown that the Akkadian Empire likely collapsed due to abrupt drought and civil turmoil. However, the climatic dynamics which caused widespread agricultural failures and the end of an era have yet to be sufficiently explored.
Researchers from Hokkaido University, the KIKAI Institute for Coral Reef Sciences, Kyushu University, and Kiel University made paleoclimatic reconstructions of the temperature and hydrological changes of the areas around the archaeological site of Tell Leilan, the center of the Akkadian Empire. They sampled six 4,100-year-old fossil Porites corals from the Gulf of Oman, just directly downwind. The samples were aged by radiocarbon dating and geochemically analyzed to confirm they have not been significantly altered from their present state.
Takaaki K. Watanabe, Tsuyoshi Watanabe, Atsuko Yamazaki, Miriam Pfeiffer. Oman corals suggest that a stronger winter shamal season caused the Akkadian Empire (Mesopotamia) collapse. Geology, 2019;
The Akkadian Empire was the first united empire in Mesopotamia and was established at 4.6 kyr B.P. (where the present is A.D. 1950). The empire abruptly collapsed in 4.2 ± 0.2 kyr B.P. Seasonal-scale climatic dynamics behind this collapse have not yet been resolved. Here, we present monthly climatic parameters (temperature and hydrology) inferred from fossil Omani corals that lived between 4.5 and 2.9 kyr B.P. Winter temperatures derived from a modern Omani coral correlate with winter shamal (western Asian dust storm) frequency. A fossil coral from 4.1 kyr B.P. shows a prolonged winter shamal season with frequent shamal days. This likely caused agricultural failures in Mesopotamia and contributed to the Akkadian Empire collapse, as this region depends on winter rainfall.