Robert Dull: Has ‘Perfect Storms’ solved AD 536 mystery?

From the Chronicle Journal:

Victoria Ahearn, The Canadian PressFriday, April 5, 2013 – 06:00TORONTO – American paleoecologist Dr. Robert Dull believes he’s pretty much solved the mystery behind a catastrophic global climate change event from the sixth century.As the new History series “Perfect Storms” shows, Dull has found solid circumstantial evidence that an eruption at El Salvador’s Lake Ilopango volcano was the cause of the so-called Dust Veil of AD 356, when a thick dust and ash cloud over the Northern Hemisphere cooled parts of the Earth and led to millions of deaths.

It’s perhaps a major breakthrough for experts who have long wondered whether the dust veil was a result of a volcanic eruption, a meteorite or a comet that slammed into Earth.”I hate to say that it’s 100 per cent, but it’s 99 per cent in my mind done (that) Ilopango was the cause of the AD 536 climate cooling that lasted for at least two years, globally, but definitely as much as a decade in terms of cooler temperatures, crop failures across the globe, and a major catastrophe that killed millions of people,”
Dull, an assistant professor at the University of Texas at Austin, said in a recent interview.”Perfect Storms,” premiering Monday at 9 p.m. ET/PT in Canada, investigates major natural disasters that have changed the course of human history — many from hundreds of years ago that aren’t well known — and presents them through impressive CGI technology and dramatic re-enactments.In Dull’s episode called “Dark Age Volcano” — airing Monday, April 15 — he finds a tree in El Salvador that he believes was living at the time of the eruption of Ilopango, one of the biggest volcanoes in central America, around 1,500 years ago.After putting it through radiocarbon dating and tree ring analysis, he’s able to date the eruption to a window of sometime between AD 500 and AD 540 and concludes it was most likely the culprit of the AD 536 global climate change that led to famine and disease.
Until Dull’s findings, scientists had only been able to date the eruption to a window of 120 years, sometime between about AD 420 and AD 540 — a range too big to be conclusive that it was behind the AD 536 event.”We’ve got it narrowed down to just a couple of decades. We’re on the verge of this perfect story to explain this perfect storm event,” said Dull.”There’s no doubt in my mind, at this point, we’ve identified the cause of the greatest climate cooling anomaly on the globe in the last 2,000 years.”Dull said his theory is that Ilopango erupted in AD 535, leading to the AD 536 dust veil that led to a global cold period that lasted at least another decade. The eruption had such a major cooling effect on the environment because it was in a tropical region.
So, do his findings have the potential to change history books?”I think it’ll slowly creep into history books,” said Dull. “But what we know for sure is that the early sixth century was a time of major pivotal change throughout the Northern Hemisphere, throughout the globe, really, in many different societies, and this is one explanation, this climate event.”As for whether this type of event could happen again, Dull said it’s possible.”Ilopango having this type of eruption again, it could happen. There have been two massive eruptions before this one, but tens of thousands of years before and neither of those two early eruptions were as large as this one,” he said.”But there are other volcanoes like Ilopongo that will most certainly erupt at some point in time.”