Yale Professor Joe Manning Presents

Date: Friday, October 19, 2018 

Time: Noon - 1pm

Location: Desert Research Institute - 2215 Raggio Parkway, Room Stout A, RENO, NV

Teleconferenced to Room SNSC 182, 755 E Flamingo Rd, Las Vegas, NV

RSVP: Visitors welcome – please RSVP to Maria Vasquez (maria.vasquez@dri.edu) 

 This lecture presents a summary of recent work connecting explosive volcanic eruptions and Nile River flow. The key insight began with the finding that explosive volcanic eruptions can be linked to a reduction in global precipitation. Eruptions affect climate by producing reflective sulfate aerosols that reduce solar radiation reaching the Earth’s surface. Less energy at the ocean surface reduces evaporative flux of water to the atmosphere. This process is particularly dramatic in the case of the African monsoon that drove annual flooding of the Nile prior to modern river management. We recently identified a clear connection between explosive volcanic eruptions, Nile flood suppression, and social unrest in Ptolemaic Egypt from 305 to 30 BCE (Manning et al., Nature Communications, 2017). Because the scale and dating of large eruptions can now be precisely determined from the latest ice-core records, we created a time series instrument to gauge social responses, such as revolt against elite rule, to reduced Nile flooding and consequent lower food production. Using that instrument, we can see dynamic responses and a series of events that likely relate to the level of Nile River flooding. These events had dramatic consequences for Ptolemaic rule in Egypt, something that we only now are beginning to understand.