Quantifying a 1.5 ^o C Fair Share Carbon Budget: Human Rights Obligations on Climate Change after <i>KlimaSeniorinnen</i>

Abstract In the face of an escalating climate crisis, climate litigation is increasingly being utilized as a means to set boundaries to States’ lack of climate action. In what stands as one of the most consequential climate cases to date, the European Court of Human Rights (ECtHR) determined in Verein KlimaSeniorinnen Schweiz and Others v. Switzerland that individuals have a human right to protection against the adverse effects of climate change. Through an in-depth analysis of the judgment, this Article explains the Court’s ruling that effective protection of human rights requires States to base their emissions reduction targets on a quantification of their fair share national carbon budgets in relation to the remaining global carbon budget for 1.5 o C. This has far-reaching implications for the scrutiny of States’ emissions reduction targets. The Article shows that, as a consequence of the rapidly depleting remaining carbon budget for 1.5 o C, States may no longer be able to remain within their fair share through domestic reductions alone. In such circumstances, States need to contribute to emissions reductions outside of their territory and reduce their domestic emissions at their highest level of ambition.