Dr. Harvey Weiss, Professor of Near Eastern Archaeology, spent his first ten years at Yale University studying how Tell Leilan, a capitol of the North Mesopotamian Kingdom evolved into an urban center. He’s spent the subsequent 20 years exploring the hypothesis that abrupt climate change brought it all down.
Director of Yale’s Tell Leilan project since 1978, it wasn’t until the early 90s that Dr. Weiss decided that regionally extensive site abandonments and a lens of wind-blown sand repeatedly encountered in the course of excavations suggested a mega-drought that explained not just the fall of Tell Leilan, but the fall of other major civilizations from the Aegean to the Indus.
The first publication in 1993 in the journal Science presenting this radical idea was met with considerable skepticism by archaeologists and paleo-climatologists. Neither discipline considered abrupt century-scale droughts as a feature of post-glacial climates in West Asia nor other parts of the world. Societies didn’t collapse because of climate change. They collapsed because of stressors such as internal conflict, poor leadership, lead in their pipes. Harvey’s idea challenged all those notions.
It wasn’t until 1993 that Professor Peter deMenocal, a climatologist from Columbia University’s Lamont Doherty Earth Observatory, saw Harvey’s work featured in a National Geographic story opposite his own in a special edition dedicated to the year’s great ideas. He read the story and recognized that Harvey needed the sort of evidence that deMenocal’s work with sea-floor sediments could provide. In cores from the Gulf of Oman he found a huge dolomite spike that could be traced to prolonged drought on the Mesopotamian Plateau, confirming that evidence of abrupt climate change in the Holocene was there if you looked for it. Further evidence was presented by Jerry Lemcke and Mike Sturm at Lake Van in Turkey and multi-national groups examining the diminution of Nile River flow at precisely the same time corresponded to the 2200 BC collapse of Tell Leilan, the Old Kingdom in Egypt and Early Helladic civilization in Greece, as Weiss had hypothesized in his 1993 article.
From controversy to acceptance, the archaeological world’s opinion on abrupt climate change and its significance for past civilizations has turned upside down. This year Harvey Weiss is a keynote speaker at four separate conferences devoted to the topic. One of the biggest, convening 20 archaeologists, historians and paleo-climatologists began in Urbino, Italy June 17. Funded by the Italian Ministry of Environment and co-sponsored by YCEI, “Past Climate Change and Societal Disruption” focuses on the role of climate in the collapse of the Maya civilization. It extends the discussion to a society where deforestation may have exacerbated naturally occurring aridification.
For Harvey Weiss and Peter deMenocal it will be a reunion and chance to extend their decades-long relationship and a collaborative process wherein archaeologists and climate scientists are helping each other make the case that nature always bats last.