Could Natural Disasters Be Behind Historical Uprisings?

Could Natural Disasters Be Behind Historical Uprisings?

The three and a half century rule of the Greek Ptolemaic Dynasty in Egypt witnessed unprecedented social unrest.

Much of this tension may have come from Egyptians’ grating under their new foreign rulers following Alexander the Great’s conquest of Egypt. However, historian Robert Ludlow of Trinity College, Ireland contends in a new study that temporary climatic changes due to natural disasters like volcanic eruptions acted as the “trigger” that spawned unrest and rebellions.

As an agriculturally dominant society, Egypt relied on the Nile’s annual floods to support healthy harvests and keep the population well-fed and content. So vital were the Nile’s fecund floodwaters that the government levied taxes at rates according to “Nilometer” readings, devices that measured local water levels. Readings indicating excessive flooding or drought led to lower taxes, while desirable flood levels increased the tax burden.

An analysis of the historical record of rebellions and droughts during the Ptolemaic Dynasty by Ludlow and his colleagues showed a strong correlation between the two. As an example, Ludlow highlights the “Egyptian Revolt” and the 20-year-long “Theban Revolt”, both of which followed directly on the heels of heightened periods of global volcanic activity.

That droughts and floods might foster social unrest comes as no surprise to historians who have long postulated exactly such. However, the new study takes this theory a step further; tracing Egyptian droughts to their specific global climatic cause.

Extracting ice cores from Greenland and Antarctica allowed Ludlow and company to identify years when volcanic eruptions sufficiently large enough to affect global climate had taken place. Eruptions of this size deposit distinctive volcanic sulfates in the ice sheet, which are frozen in time and thus determinable to exact years. Their analysis suggested aerosol and particulate matter from these eruptions was indeed substantial enough to affect rainfall and Nile flood levels.

Historian Robert Littman of the University of Hawaii — uninvolved in the study — advises against assigning undue importance to flooding alone, however. He notes that ideal agricultural levels for the Nile varied greatly by region. This would indicate that flooding or drought in one level cannot necessarily be imported an Egypt-wide significance.

Ludlow largely concurs with this assessment. He notes that his research indicates the consequences of natural disasters acted as local triggers when societal conditions were already ripe for unrest. "We frame the volcanic eruptions and the associated failures of the Nile summer floodwaters as triggers because their impact occurs suddenly without warning” he told Ars Technica.

The foreign-rule of the Ptolemaic Dynasty and its consequent cultural and economic upheavals fits this scenario perfectly.

Predicting Future Social Unrest Based on Climate?

Still, the new study provides an opportunity to glean important lessons regarding the role natural disasters and climate change in general may play in fostering future social unrest.

The ongoing seven-year-old Syrian Civil War presents a case study in exactly this. An intense drought beginning in 2006 continuing through the beginning of the conflict in 2011 drove a dramatic migration from rural farming communities to urban areas, which upset those areas’ delicate social balance. Along with the emergent region-wide political discontent of the Arab Spring, this new, untethered urban population is thought to have played an important role in the outbreak of unrest.

Interestingly, studies of the unprecedented Syrian drought suggest it may have been amplified by anthropogenic causes, which only adds another layer to the factors governments must consider going forward.

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