This systematic literature review explores the intersection of environmental displacement and the common but differentiated responsibility (CBDR) principle, focusing on the ethical, legal, and practical dimensions of climate justice. We examine how current frameworks address disproportionate climate impacts on vulnerable populations, particularly in low-income nations, and evaluate obligations arising from historical emissions. Synthesizing research on climate migration, adaptation funding, socio-economic inequalities, and climate litigation, we identify critical gaps, including insufficient intersectional perspectives and inequitable resource allocation. Our findings emphasize the urgent need for stronger institutional mechanisms to enforce CBDR, especially for displaced individuals lacking legal protection. Although climate litigation is increasingly used to hold high-emission actors accountable, its effectiveness remains debated. Ultimately, while CBDR provides a normative foundation for addressing environmental displacement, its current application is fragmented. We conclude that unified international efforts and comprehensive policy frameworks are essential to align fairness and accountability in a warming world.