How to ‘downsize’ a complex society: an agent-based modelling approach to assess the resilience of Indus Civilisation settlements to past climate change

Abstract

The development, floruit and decline of the urban phase of the Indus Civilisation (c.2600/2500-1900 BC) provide an ideal opportunity to investigate social resilience and transformation in relation to a variable climate. The Indus Civilisation extended over most of the Indus River Basin, which includes a mix of diverse environments conditioned, among other factors, by partially overlapping patterns of winter and summer precipitation. These patterns likely changed towards the end of the urban phase (4.2 ka BP event), increasing aridity. The impact of this change appears to have varied at different cities and between urban and rural contexts. We present a simulation approach using agent-based modelling to address the potential diversity of agricultural strategies adopted by Indus settlements in different socio-ecological scenarios in Haryana, NW India. This is an ongoing initiative that consists of creating a modular model, Indus Village, that assesses the implications of trends in cropping strategies for the sustainability of settlements and the resilience of such strategies under different regimes of precipitation. The model aims to simulate rural settlements structured into farming households, with sub-models representing weather and land systems, food economy, demography, and land use. This model building is being carried out as part of the multi-disciplinary TwoRains project. It brings together research on material culture, settlement distribution, food production and consumption, vegetation and paleoenvironmental conditions.

Weather, Land and Crops in the Indus Village Model: A Simulation Framework for Crop Dynamics under Environmental Variability and Climate Change in the Indus Civilisation

“…The six experiments described here were designed to help reveal or clarify the terms of the crop choice dilemma in the IC context, even if regarding only cereal crops, and they have widely met our expectations. According to our initial theoretical formulation [21] and the present results, the conditions leading to the crop choice dilemma are the following:…”

“…More details on the TwoRains modeling program and the Indus Village overall design can be found in our previous publication [21] and the code and documentation are openly accessible under GNU GPLv3 licence in the dedicated GitHub repository [36].…”

“…Instead, as with most crop models, we must assume that the farming agency behind crop cultivation invests enough, so that all crops can be sown, maintained, and harvested successfully, according to the constraints covered in the model. However, a broader economic mechanism that integrates the factors above will make the core of the Indus Village [21,36].…”

“…The TwoRains modeling program aimed to expose the sustainability of food production regimes, especially in terms of cropping strategies, in the face of abrupt climate change. The program has led to the development of the Indus Village, a modular multi-paradigm agent-based simulation model designed to represent environmental and human factors as a single unified system [21]. Modeling has been carried out within the spirit of creating a virtual laboratory for socioecological systems, following a twodecade-wide trend in computational archaeology [22][23][24][25][26][27][28][29][30].…”

SAGAscape: Simulating Resource Exploitation Strategies in Iron Age to Hellenistic Communities in Southwest Anatolia

“…This stands in contrast with several other ABMs where randomly generated settlements with alterable, migrating populations engage in agriculture and/or material sourcing. For examples, see MayaSim (Heckbert 2013, Heckbert et al 2016), Indus Village (Angourakis et al 2020(Angourakis et al , 2022 and the family of models produced by the Village Ecodynamics Project (VEP) (Kohler et al 2012, Crabtree et al 2017.…”