Long-term trends in settlement persistence in Southwest Asia: Implications for sustainable urbanism, past, present and future

Southwest Asia saw the emergence of large settlements in the Early Holocene, and the world’s first urban communities around 6000 years ago, with cities a feature of the region ever since. These developed in diverse environmental settings, including the dry-farming plains of Northern Mesopotamia, the irrigated alluvium of Southern Mesopotamia and the more variegated landscapes of the Levant. In this paper we use a dataset of several hundred sites dating from the earliest large sites around 12,000 years ago to the Classical period (2000 BP), to examine trends in settlement sustainability through time. We use persistence of occupation as a proxy for sustainability and compare settlement trajectories in different land use zones. Comparing cities and settlements at these spatial and temporal scales allows us to address a key question in the New Urban Agendas framework: how urban development can best be supported by sustainable use of land. We find that the highest levels of persistence were not uniformly associated with high agricultural productivity regions, and some of the longest-lived settlements are located in marginal environments, likely at critical points in transport networks. We also find that persistence is enhanced in landscapes which do not require large-scale capital investment or specific forms of economic and social organisation to maintain high levels of agricultural productivity, and that sustainability is inversely correlated with social complexity. Our results show that the millennial timescales available through archaeology can enable us to identify the political, social and ecological conditions required for large centres to persist through time.