Sharing the Burdens of Climate Mitigation and Adaptation: Incorporating Fairness Perspectives into Policy Optimization Models

Abstract

Mitigation of, and adaptation to, climate change can be addressed only through the collective action of multiple agents. The engagement of involved agents critically depends on their perception that the burdens and benefits of collective action are distributed fairly. Integrated Assessment Models (IAMs), which inform climate policies, focus on the minimization of costs and the maximization of overall utility, but they rarely pay sufficient attention to how costs and benefits are distributed among agents. Consequently, some agents may perceive the resultant model-based policy recommendations as unfair. In this paper, we propose how to adjust the objectives optimized within IAMs so as to derive policy recommendations that can plausibly be presented to agents as fair. We review approaches to aggregating the utilities of multiple agents into fairness-relevant social rankings of outcomes, analyze features of these rankings, and associate with them collections of properties that a model’s objective function must have to operationalize each of these rankings within the model. Moreover, for each considered ranking, we propose a selection of specific objective functions that can conveniently be used for generating this ranking in a model. Maximizing these objective functions within existing IAMs allows exploring and identifying climate polices to which multiple agents may be willing to commit.

Efficiency or equality? The utilitarianism–egalitarianism trade‐off determines carbon allocation preference

“…What, then, determines decisions in the efficiency–equality dilemma in carbon allocation? Research from the intergroup bias perspective suggests that the diverse preferences for carbon allocation arise from competition over interests (Kartha et al., 2018; Shukla, 2019; Skott & Davis, 2013; Żebrowski et al., 2022). Given their historically higher carbon emissions, highly industrialized nations endorse the efficiency approach to diminish the emphasis on historical responsibilities during allocation, thereby lessening their supposedly more stringent emission reduction obligations.…”

“…Given their historically higher carbon emissions, highly industrialized nations endorse the efficiency approach to diminish the emphasis on historical responsibilities during allocation, thereby lessening their supposedly more stringent emission reduction obligations. Conversely, less industrialized nations advocate the equality approach to gain more allowance for future emissions (Manne & Stephan, 2005; Timmons Roberts & Parks, 2007; Żebrowski et al., 2022).…”

“…Extant international carbon allocation proposals can be broadly divided into two categories that underline either efficiency or equality (Pan et al., 2014, 2023). The efficiency approach prioritizes rapid and efficient global emissions reduction (Żebrowski et al., 2022). For example, the emissions intensity method suggests that carbon credits should be proportionally skewed towards nations that require lower emissions per unit of GDP because they consume fewer credits to produce the same economic benefits and are therefore more capable of reducing emissions efficiently (Zhou & Wang, 2016).…”

“…Previous research has explained the ongoing debate among nations about whether carbon allocation should follow efficiency or equality approaches from an intergroup bias perspective (e.g., Kartha et al., 2018; Shukla, 2019; Skott & Davis, 2013; Żebrowski et al., 2022). The international community is divided into two carbon emissions camps: highly industrialized nations with historically high carbon emissions and less industrialized nations with historically low carbon emissions (Swim & Bloodhart, 2018).…”

“…The efficiency approach, which requires high‐emissions reduction in less industrialized nations, enables highly industrialized nations to evade more stringent reduction responsibilities and is therefore favoured by them (Caney, 2010; Cuomo, 2011; Resnik, 2022). In contrast, the equality approach assigns much lower emissions reduction targets to less industrialized nations, while requiring highly industrialized nations to reduce emissions sharply, and is therefore supported by less industrialized nations (e.g., Shukla, 2019; Żebrowski et al., 2022).…”