Quantifying Compliance: Article 8 Carbon Budgets as Proof of ICJ-Level Due Diligence

Abstract

States increasingly formalize their climate change commitments in the language of  net-zero deadlines, interim emission targets, and carbon budgets,  raising the question of whether these quantified benchmarks serve as evidence of legal compliance. This research paper investigates whether Article 8 ’requirements for quantifying climate action (in particular, the European Court of Human Rights’ recent insistence on timelines, interim targets, and carbon budgets) are probative of a state’s compliance with the International Court of Justice (ICJ)’s due-diligence standard for climate obligations. We analyze converging developments in human rights and international law: the Klimaseniorinnen judgment of April 2024, where the ECtHR held that states must enact binding climate targets and carbon budgets to protect the right to private life, and the ICJ’s 2025 Climate Change Advisory Opinion confirming states’ duty of “stringent” due diligence to prevent foreseeable climate harm. Our findings indicate that quantified climate action frameworks are not only politically salient but also legally significant. Their presence (or absence) is treated as compelling evidence of whether a state is meeting its international obligations. However, we argue that while such “numbers that bind’ are necessary indicators of due diligence, they are not sufficient ambition, and implementation remains paramount.