Harvey Weiss is an archaeologist, famous for the discovery of Tell Leilan

Tell Leilan

Tell Leilan is an archaeological site situated near the Wadi Jarrah in the Khabur River basin in Al-Hasakah Governorate, northeastern Syria. The site has been occupied since the 5th millennium BC. During the late third millennium, the site was known as Shekhna...

, and who teaches at Yale University

Yale University

Yale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...

 as well as directing the excavations and surveys at Tell Leilan, Syria, during the summers. His most-discussed contribution to the Archaeological Anthropological field has been his hypothesis that certain major climate changes have done much to alter prehistoric and ancient societies' developmental trajectories, such as the abrupt climate change

Abrupt climate change

An abrupt climate change occurs when the climate system is forced to transition to a new state at a rate that is determined by the climate system itself, and which is more rapid than the rate of change of the external forcing...

 4,200 years before present that reduced agricultural production in northern Mesopotamia, reduced and disrupted Akkadian imperial revenues there, and thereby forced the Akkadian political collapse in southern Mesopotamia Akkadian Empire.