Homophily and wealth inequality shape mitigation behavior in coupled social-climate models
Luke Wisniewski, Thomas Zdyrski, Feng Fu
TL;DR
The paper develops a coupled forest-vegetation and social-dynamics framework to study how wealth inequality and homophily shape mitigation behavior. It links a temperature-sensitive vegetation growth model with two-group evolutionary game dynamics, where mitigation decisions depend on payoffs $E_i(M)$, $E_i(N)$, a social-norm term $oldsymbol{ abla}$, and a dissatisfaction-adjusted cost for the poor group, integrating these into a three-equation coupled system via $x= ext{min}ig\{s ho x_R+(1- ho)x_P,1ig\}$ and $oldsymbol{ abla}(x)=0.2+0.4x$. Through stability analysis and extensive parameter sweeps, the study shows that homophily can either worsen or improve environmental outcomes depending on parameter regimes (e.g., ambient temperature $T_v$, critical temperature $T_c$, mitigation effectiveness $s$, and norms $oldsymbol{ abla}$). These results reveal tipping-point-like behavior and emphasize that social structure and inequality critically modulate climate action trajectories, with policy implications for leveraging norms and targeted cooperation to sustain vegetation and mitigate warming. The work advances interpretability in social-climate dynamics and provides a testbed for exploring how inequality and echo chambers affect collective-risk dilemmas in environmental settings $($forest dieback$)$.
Abstract
Understanding the role of human behavior in shaping environmental outcomes is crucial for addressing global challenges such as climate change. Environmental systems are influenced not only by natural factors like temperature, but also by human decisions regarding mitigation efforts, which are often based on forecasts or predictions about future environmental conditions. Over time, different outcomes can emerge, including scenarios where the environment deteriorates despite efforts to mitigate, or where successful mitigation leads to environmental resilience. Additionally, fluctuations in the level of human participation in mitigation can occur, reflecting shifts in collective behavior. In this study, we consider a variety of human mitigation decisions, in addition to the feedback loop that is created by changes in human behavior because of environmental changes. While these outcomes are based on simplified models, they offer important insights into the dynamics of human decision-making and the factors that influence effective action in the context of environmental sustainability. This study aims to examine key social dynamics influencing society's response to a worsening climate. While others conclude that homophily prompts greater warming unconditionally, this model finds that homophily can prevent catastrophic effects given a poor initial environmental state. Assuming that poor countries have the resources to do so, a consensus in that class group to defect from the strategy of the rich group (who are generally incentivized to continue ``business as usual'') can frequently prevent the vegetation proportion from converging to 0.