Scientists have discovered extraordinarily precise data on rainfall in the Mediterranean region from 200 B.C. to 1100 A.D. which suggests that the fall of the Roman and Byzantine empires may have been partly caused by climate change.
It is not likely to end the debate among historians, some of whom believe the fall was more of a transformation than a collapse, but it is a tantalizing bit of evidence. And the way it was collected is as intriguing as the fact that researchers can now analyze rainfall on a year-to-year basis, season to season, even many thousands of years ago.
For more than 15 years geology professor John Valley of the University of Wisconsin-Madison, has been studying stalactites from a cave near Jerusalem, along with scientists at the Geological Survey of Israel and Hebrew University. His Israeli colleagues have dated some of the stalactites to about 185,000 years ago, and they have reconstructed broad climate fluctuations over many years because the formation of the calcite deposits depends partly on rainfall.