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.”