Establishing State Responsibility in Mitigating Climate Change under Customary International Law

As acknowledged in the Paris Agreement’s Preamble, climate change is a “common concern of humankind.” To tackle the anthropogenic greenhouse gases (GHGs) at source, State governments played a pivotal role in implementing climate change policies. It thus justifies the approach of looking into the solutions to climate change from a state responsibility perspective. As mentioned by James Crawford, “[a]ny system of law must address the responsibility of its subjects for breaches of their obligations.” The finding of state responsibility in mitigating climate change will complement the treaty-based climate change regime, providing grounds for climate change litigations and policy formulation. More than 50 years ago, the International Court of Justice (ICJ) stated that there are two types of state responsibility in Barcelona Traction: a state-to-state duty and obligations erga omnes (i.e., duties owed to the international community as a whole). Later, the International Law Commission (ILC) codified the state responsibility principles in the Articles on the Responsibility of States for Internationally Wrongful Acts (ARSIWA). In the context of climate change, the issue is that there is currently no international authority directly recognizing the state responsibility to mitigate climate change, except in climate change treaties and soft law. Thus, this article seeks to broaden such state responsibility by drawing inferences from general principles and establishing new legal grounds. States owe an obligation not to cause harm to one another under the no-harm principle. There is also a due diligence obligation to prevent climate change harm. The joint-and-several duties and common-but-different-responsibility (CBDR) principles emphasize that such duties are shared collectively by States. By adopting the human rights approach, it argues that States’ climate change obligations are erga omnes. The recent trend of creating rights for nature will further contribute to state responsibility’s jurisprudence to mitigate climate change. For the structure of this article, Part II will explain the background and motivation of research. Part III will briefly introduce the law of state responsibility. Part IV will discuss the details of the duty to mitigate climate change. There is a conclusion in Part V