Old Climate Clues Shed New Light on History

The Climate Desk collaboration has a story on Yale Environment 360.

The moment when Joseph Manning was shown an advance copy of a scholarly paper that pinpointed the timing of major volcanic eruptions over the last 2,500 years is one he likes to remember. He said recently that he fell off his chair as he read the paper.

The paper, published in Nature in 2015, showed that major eruptions worldwide caused a long-term drop in global temperatures. Research pegged those drops at as much as 13 degrees F.

Manning was shocked by the paper's suggestion that the dates of the eruptions coincide with well-known political, social, and military upheavals over three centuries of ancient Egyptian history. The paper correlated volcanic eruptions with major 6th century A.D. pandemics, famines, and socioeconomic turmoil in Europe, Asia, and Central America. The paper argued that volcanic soot, which cools the earth by shielding it from sunlight, helped cause those crises.

Since then, other scholarly papers using paleoclimatic data have found many instances when shifts in climate helped cause social and political tumult. A paper that was published last month in Communications Earth and Environment theorizes that there is a correlation between volcanic eruptions and collapse in Chinese history.

If the eruptions and collapses were unrelated, the study found that 62 of the 68 collapses occurred soon after the eruptions. The fall of dynasties has been attributed to the withdrawal of the mandate of heaven. The paper claims that the phenomena have a climatic explanation.

The revolution in climate science technology is behind all of the papers. The way some historians do their work has been upended by the flood of quantitative data from climate proxies.

Climate data is an incontrovertible, objective source of important information, according to Joe McConnell, who runs a pathbreaking ice core analytical laboratory at the Desert Research Institute in Reno, Nevada. McConnell said that the climate data is information that historians have to take in.

Some historians are crossing barriers to work with other disciplines. Historians are learning about the environment while scientists are reading history.