Do we fully understand youth climate activism and their claims for climate justice? Previous studies have mainly focused on intergenerational inequality. However, this framing is inadequate when considering youth climate movements in South Korea. Korean school strikers are characterized by their ambivalent stance toward the term "future generations" and their critical views on social injustice. This study examines their generational consciousness and environmental concerns, exploring the manifestation of three different dimensions of climate justice-intergenerational inequality, historical responsibility, and critical climate justice. Through empirical analysis, this study demonstrates the evolution of their justice claims from a basis in intergenerational inequality, to one in concepts of historical responsibility, and finally a move toward critical climate justice. Korea's history of poverty has neutralized criticisms of older generations; the age-based discrimination has led young activists to develop a fierce criticism of existing social inequalities; their experiences of political exclusion have developed a strong sense of solidarity with other marginalized groups, going beyond the narrow focus of the younger generation's interests. In conclusion, this study defines contemporary youth climate activism as a movement that demonstrates the ramifications of civic inequality and endeavors to include diverse groups in the combat against climate change.