국제사법재판소(ICJ)의 기후변화에 관한 권고적 의견과 국가책임

On July 23, 2025, the International Court of Justice(ICJ) issued a progressive Advisory Opinion that marked a landmark ruling in the field. In this groundbreaking opinion, the ICJ recognized climate change as an existential threat and not only clarified the obligations of states in respect of climate change, but also confirmed that the rules governing the responsibility of States are applicable in the context of climate change. One of the most significant advancements in the opinion is the ICJ's clear confirmation that states may incur international responsibility if they fail to control and reduce greenhouse gas(GHG) emissions. This opinion is regarded as the most significant development in international climate law since the adoption of the Paris Agreement. Through this opinion, the ICJ has significantly shaped the contours of international environmental law and global climate governance, by clarifying numerous obligations of states and their corresponding legal responsibility. The ICJ's Advisory Opinion addressed two central questions: (1) the obligations of states regarding climate change, and (2) the legal consequences of breaching those obligations—that is, the scope of State responsibility. A significant part of the opinion focuses on clarifying states’ broad primary obligations and the resulting legal consequences of non-compliance. On the issue of State responsibility, the Court affirmed that general rules of international law apply in the climate context. It examined key legal elements such as attribution of conduct, breach of international obligations, causation, the erga omnes nature of climate obligations, and available remedies and reparation. As such, the Advisory Opinion serves as a basic document for future climate negotiations and accountability processes. Despite the complexities of attribution, causation, and temporal scope, the ICJ concluded that when a State commits an act attributable to it that violates its climate obligations, this constitutes an internationally wrongful act, giving rise to State responsibility and a duty to provide reparation. Notably, the Court stated that a State’s failure to take appropriate measures to protect the climate system from GHG emissions may amount to such a wrongful act. Under the general rules of State responsibility, the legal consequences include: (i) cessation of the wrongful act and guarantees of non-repetition, and (ii) an obligation to provide full reparation, which includes restitution, compensation, and satisfaction. This paper analyzes the key legal issues related to the second question addressed by the ICJ—namely, the legal consequences of breaching climate-related international obligations—and discusses their significance under international law.