Abstract While social inequality limits the less affluent’s ability to support climate action, we develop a theoretical framework that analyzes how disadvantageous inequality aversion diminishes motivation for climate cooperation among the broader population. By clarifying how perceptions of disadvantage or social injustice can harm climate cooperation or produce backlash, we derive tailored countermeasures to enhance climate cooperation. Introduction Why do some climate policies spark widespread public support while others ignite protests and backlash? Understanding the role of inequality aversion may hold the key. Scholars have argued that social inequality threatens the goals of the Paris Agreement. Contributing to climate change mitigation is often individually costly, requiring additional expenditure on climate-friendly transport and food, adopting green technologies, and paying climate change taxes. Economic constraints can be a serious barrier for the less privileged, as climate action puts a greater strain on their budgets due to lower incomes and assets 1 , 2 , 3 . The significance of another key factor related to inequality that can undermine support for climate policy and action is less well understood: inequality aversion (see Box 1 for a detailed explanation of this and other key concepts discussed in the following paragraphs). This refers to the disutility caused by differences between one’s own economic situation and that of others, which can dampen intrinsic motivation to support climate action. The Yellow Vest movement in France in 2018 illustrates this effect. The protests erupted in response to a carbon tax increase and were fueled by earlier tax cuts for affluent individuals, demonstrating the potential for public backlash against climate policies perceived as unfair 4 , 5 . Numerous other countries have experienced similar public backlash against climate policies 6 , 7 . Addressing inequality aversion is critical to preventing backlash and fostering both support for climate policies […]