Societal breakdown as an emergent property of large-scale behavioural models of land use change

Abstract

Abstract. Human land use has placed enormous pressure on natural resources and ecosystems worldwide, and may even prompt socio-ecological collapses under some circumstances. Efforts to avoid such collapses are hampered by a lack of knowledge about when they may occur and how they may be prevented. Computational models that illuminate potential future developments in the land system are invaluable tools in this context. While such models are widely used to project biophysical changes, they are currently less able to explore the social dynamics that will be key aspects of future global change. As a result, strategies for navigating a hazardous future may suffer from blind spots at which individual, social and political behaviours divert the land system away from predicted pathways. We apply CRAFTY-EU, an agent-based model of the European land system, in order to investigate the effects of human-behavioural aspects of land management at the continental-scale. We explore a range of potential futures using climatic and socio-economic scenarios, and present a coherent set of cross-sectoral projections without imposed equilibria or optimisation. These projections include various behavioural responses to scenarios including non-economic motivations, aversion to change, and heterogeneity in decision-making. We find that social factors and behavioural responses have dramatic impacts on simulated dynamics, and can contribute to a breakdown of the land system's essential functions in which shortfalls in food production of up to 56 % emerge. These impacts are largely distinct from, and at least as large as, those of projected climatic change. We conclude that the socio-economic aspects of future scenarios require far more detailed and varied treatment. In particular, the extent of economic irrationality at individual and aggregate scales may determine the nature of land system development, with established pathways being highly vulnerable to deviation from this theoretical optimum.

Food and nutrition security under global trade: a relation-driven agent-based global trade model

“…Using a large-scale simulation model of land-use change, Brown et al . [ 4 ] show that social and behavioural factors can drastically change local land use and cause severe food shortages of up to 56% without climatic disturbances. Hammond and Dubé [ 5 ] argue that food and nutrition security is driven by complex underlying systems at both local and regional/global scales.…”

How can social–ecological system models simulate the emergence of social–ecological crises?

“…Another existing approach with notable relevance is the use of functional typologies to describe and model social or ecological dynamics (Grêt‐Regamey et al, 2019; Rocha et al., 2019). Indeed, this functional approach has already been transferred from ecological modelling to social–ecological modelling as an efficient method of capturing major forms of human activity (Arneth et al., 2014; Brown, Seo, et al., 2019; Grêt‐Regamey et al., 2019). In this case, functional typologies have been developed to represent not only the environmental requirements and contributions of different land managers but also their decision‐making characteristics (e.g.…”

“…In general, these analyses conclude that process‐based approaches such as agent‐based modelling (ABM) have particular promise for simulating key processes because they have an established history of representing social and ecological dynamics as emergent from such processes, and attempting to realistically represent real‐world problems on this basis (Gras et al., 2009; Schlüter, Müller, et al., 2019). ABM is already used to represent the human decision‐making that mediates social and environmental interactions (Egli et al., 2019; Groeneveld et al., 2017; Lippe et al., 2019; Schulze et al., 2017) including in the contexts of breakdowns in large‐scale food systems (Brown, Seo, et al., 2019) and marine fisheries management (Gao & Hailu, 2012). It has also been used to some extent to identify high‐level or cross‐context processes (Parker et al., 2008) and their relative impacts on social–ecological change (Brown, Holzhauer, et al., 2018).…”

“…Encouragingly, models that have adopted some of these methods to simulate fundamental social–ecological processes have repeatedly generated emergent dynamics that differ substantially from those produced by correlative or single‐sector models, including dynamics that produce potential crises related to climatic, environmental and social change (Brown, Seo, et al., 2019; Bury et al., 2019; Lade et al., 2013; Synes et al., 2019; Ullah, 2013). Upscaling these approaches to make them operate over the large geographical extents relevant to major crises currently remains an acknowledged challenge, but one for which progress is being made (Elsawah et al., 2020; Robinson et al., 2018).…”

“…Most obviously, it could extend the ability of process‐based models to simulate the emergence of breakdowns and crises (e.g. Brown, Seo, et al., 2019; Ullah, 2013) to other contexts and scales. Such simulation is strictly distinct from prediction (see below), but it can reveal situations and dynamics from which crises can emerge that might otherwise not be recognised, opening up potential opportunities for designing new interventions.…”