The strongest short-term cooling event on Earth over the past 2000 years occurred from 536-550 of the Common Era. Historical accounts of an atmospheric dust veil in AD 536 were reported in many locations throughout the northern hemisphere during this time, including: the Mediterranean basin, the British Isles, and China. Summer crop failures and famine were also widespread during this period, with some scholars suggesting that as many as 50 million fatalities can be traced to this event. Historians have also linked several pivotal world events around this time to the strong 6th century cooling, most notably the first bubonic plague pandemic in Europe (“Plague of Justinian”), a weakening of the eastern Roman Empire, and the rapid ascent of Islam. Although some scientists initially believed that the global cooling might have been caused by a comet or asteroid impact, evidence has emerged over the past decade to implicate a series of strong volcanic eruptions. Evidence from ice cores in Greenland and Antarctica suggest that the three separate eruptions occurred in AD 536, 540, and 547. The second of these was apparently the largest of the three and was of tropical origin. The eruption of Ilopango Volcano in El Salvador is thought to be the AD 540 ‘mystery’ tropical volcano that pushed the planet into a food security crisis during the 6th century. This eruption was a magnitude 7 on the Volcanic Explosivity Index, ranking it as one of the top 10 largest eruptions on Earth over the past 10,000 years.

Join us as we examine the eruption of Ilopango Volcano and explore the regional impacts on Central America during this time, including the suggestion that 250,000+ Maya might have perished as a direct result of scorching pyroclastic flows and thick deposits of ash covering all of El Salvador and adjoining regions of Honduras and Guatemala.

Dr. Robert Dull is the Chair of the Department of Earth and Environmental Sciences at Cal Lutheran. His research seeks to elucidate human-environment relationships over time, with emphases on the Late Prehistoric and Colonial periods in the Americas. Dr. Dull works on topics ranging from deforestation and food production to climate change and natural hazards. He has spent most of his career working in Central America, although he also has ongoing research projects in California. Dull’s work on Ilopango has been featured by many outlets, including Science Magazine, Forbes, New Scientist, and National Geographic. Dr. Dull grew up in Bakersfield, CA and received his Ph.D. from the University of California, Berkeley in 2001. Before arriving at CLU in 2019 to Chair the newly formed Department of Earth & Environmental Sciences, he held full-time academic appointments at UC Berkeley, Texas A&M University, and the University of Texas, Austin.