The record, published in the journal Science Advances, shows that the period between roughly A.D. 200 and 800 was far drier than any time during the previous 10,000 years. This may have been the cause of the downfall of the Han, Tang, and Ming dynasties, all of which were based in what is now China.
The stalagmite was collected from Yongning Cave, located in the central Chinese province of Hubei. Stalagmites are formed by the slow accumulation of calcite, which is a mineral that is deposited by water dripping from the ceiling of a cave. The thickness of the calcite layers can be used to reconstruct past rainfall patterns, since more rain leads to more water dripping into the cave and more calcite being deposited.
The Yongning Cave stalagmite is particularly valuable because it contains a continuous record of rainfall dating back 10,000 years. This allowed the researchers to compare the rainfall patterns during the rise and fall of the Han, Tang, and Ming dynasties.
The results show that the driest period in the stalagmite record occurred between roughly A.D. 200 and 800. This period corresponds to the decline of the Han, Tang, and Ming dynasties. The researchers believe that the drought may have caused crop failures, water shortages, and other problems that led to the downfall of these empires.
The study provides new evidence for the role of climate change in the collapse of ancient civilizations. It also suggests that future climate change could have a similar impact on modern societies.
"The Yongning Cave stalagmite record provides a cautionary tale about the potential impacts of climate change," said study co-author Hai Cheng. "If future climate change leads to more droughts, this could have a devastating impact on human societies."
