August 14, 2015

Chinese cave ‘graffiti’ tells a 500-year story of climate change and impact on society

image: Inscription from 1891 found in Dayu Cave. Credit: L. Tan

(August 14, 2015)  Unique inscriptions found in a cave in China, combined with chemical analysis of cave formations, show how droughts affected the local population over the past five centuries, and underline the importance of implementing strategies to deal with climate change in the coming years.

An international team of researchers, including scientists from the University of Cambridge, has discovered unique ‘graffiti’ on the walls of a cave in central China, which describes the effects drought had on the local population over the past 500 years.

The information contained in the inscriptions, combined with detailed chemical analysis of stalagmites in the cave, together paint an intriguing picture of how societies are affected by droughts over time: the first time that it has been possible to conduct an in situ comparison of historical and geological records from the same cave. The results, published in the journal Scientific Reports, also point to potentially greatly reduced rainfall in the region in the near future, underlying the importance of implementing strategies to deal with a world where droughts are more common.

 The inscriptions were found on the walls of Dayu Cave in the Qinling Mountains of central China, and describe the impacts of seven drought events between 1520 and 1920. The climate in the area around the cave is dominated by the summer monsoon, in which about 70% of the year’s rain falls during a few months, so when the monsoon is late or early, too short or too long, it has a major impact on the region’s ecosystem.

 “In addition to the obvious impact of droughts, they have also been linked to the downfall of cultures – when people don’t have enough water, hardship is inevitable and conflict arises,” said Dr Sebastian Breitenbach of Cambridge’s Department of Earth Sciences, one of the paper’s co-authors. “In the past decade, records found in caves and lakes have shown a possible link between climate change and the demise of several Chinese dynasties during the last 1800 years, such as the Tang, Yuan and Ming Dynasties.”

journal reference (Open Access)  >>