Environmental (in)justice (EJ) research confronts the issue of whether environmental harms (aka “disamenities”) are disproportionately placed in minority communities and, if so, what mechanisms lead to this outcome. Several hypotheses such as firms’ discriminatory decisions, market dynamics, or other institutional practices have been posed to explain causal drivers of observed EJ outcomes. Over some years we have presented our ongoing research project using agent-based modeling to explore societal environmental injustices – what factors substantially contribute to the issue (Eckerd, Campbell and Kim 2012; Kim, Campbell and Eckerd 2013) or where an institutional deign feature such as zoning can lessen the environmental gap between majorities and minorities (Campbell, Kim and Eckerd, 2014). These research presentations demonstrated the utility of Agent-Based Modeling (ABM) as a policy analysis tool in disentangling the complexity of social and policy processes. 

In our previous research, we have noted that lack of mobility in the model may be a potential problem through excess influence on our findings. In order to explore the relationship between residential mobility and EJ outcomes, the paper proposed for the 2014 conference will add residents’ ability to move, when they can find better environmental quality, to the ABM we have built. Tiebout (1956) suggests that residential mobility enables observation of how much residents are willing to pay for public goods such as environmental quality. People always can “vote with their feet” and decide to live in whichever community best meets their preferences for public goods. However, this assumption is quite strict and, most problematically, an assumption of full and costless mobility is clearly at odds with observed patterns of settlement – residents have some level of mobility, but they do not consider whether they would like to move every day. The assumptions of full mobility and no mobility are equally problematic. Some existing empirical evidence suggests that observed mobility trends in the US are somewhere between 10% and 35% (Lee and Wadell 2010, Ferreira 2007; Deilman 2001). Based on theoretical and empirical evidence of residential mobility, in this paper, we analyze an array of mobility assumptions and mobility’s impact on EJ outcomes.

Our preliminary analysis presents three important findings: 1) even with the Tiebout assumption of full mobility, minorities are not generally better off in terms of average environmental quality; 2) even when mobility is modeled, residential similarity preferences have a stronger effect on how majorities and minorities experience environmental quality; 3) thus, societal environmental injustice is still primarily a function of racial awareness of residents rather than their mobility in a neoclassical world.

The presence of minority-based environmental injustice is a troubling policy problem. The use of ABM can help us explore many sets of causes, including emergent unintended ones. Understanding causes should help us develop more effective policies. In addition, ABM, with its ability graphically to represent complex phenomena, can communicate with policymakers.