Thank you for your notes. Really quite interesting. I was not aware that the dating of the Hekla eruption was so disputed. The reason I focussed on it was that droughts seemed to me like they played a crucial role. The research by Drake et al. argued (relying on isotope data) that this drought was caused by a cooling of the sea, which in turn needs an explanation. And the most likely explanation seemed to be a volcanic eruption.
But I agree that it is overall very hard to understand the timing of all those events. Especially as it played out differently in different parts of the region. In some regions maybe the pandemic struck first, while it was migration or drought in others. I had hoped to highlight this complex web in my second figure.
Thanks! Interesting to hear what kind of evidence we have that points toward droughts and volcanic eruptions.
Note that overall I’m very uncertain how much to discount the Hekla eruption as a key cause based on the uncertain dating. This is literally just based on one sentence in a Wikipedia article, and I didn’t consult any of the references. It certainly seems conceivable to me that we could have sufficiently many and strong other sources of evidence that point to a volcanic eruption that we overall should have very high credence that the eruption of Hekla or another volcano was a crucial cause.
Guys, great post and discussion. I was taking a look at the discussion about Hekla’s role… even if the eruption succeeded the breakdown of those civilizations by half a century, it’d likely have an effect concerning their prospects for recovery.