This is scientific American 62nd Science. I'm Cynthia Graber. Got a minute?

Historical instances of dramatic societal upheaval have been attributed to changes in climate.

Now a cave in China has been attributed to changes in climate.

Now a cave in China has been shown to contain both physical evidence for specific periods of

drought and written records of the hardships in the form of graffiti by people suffering

from those droughts.

The findings are in the journal Scientific Reports.

During the past 500 years, people made regular pilgrimages

to the Dayu Cave in the Chinling Mountains of Central China.

During seven of the visits, the oldest one going back

to the year 1520, Pilgrims left messages

on the cave walls related to droughts.

Researchers were able to link those graffiti,

which contained dates, to physical evidence of the water shortages.

For example, lack of water caused changes in ratio of stable isotopes in specific layers of cave formations such as stalagmites.

The site has thus provided the first known case of historical and geological records existing

in the same cave.

Cambridge University Earth Scientist Sebastian Breitenbach is a co-author of the study.

He says that records found in caves and lakes in the last decade reveal possible links between

climate change and the downfall of several Chinese dynasties including the Tang and Ming.

He also notes, quote, things in the world are different from when these cave inscriptions are written,

but we're still vulnerable to these events, especially in the developing world.

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