How can national courts contribute fairly to climate justice?

National courts have become major actors in disputes about climate justice, as they have been asked to regulate national mitigation action. Often, claimants and legal scholars alike have argued that the state should stick to certain emissions pathways. Against that, national courts and opposing legal scholars have argued that the determination of national emissions pathways is a political matter, and thus should be left to the legislator. In this paper, we address the role of national courts in climate justice issues. We identify three criteria for the fair contribution of national courts to climate justice: the democracy criterion (Criterion 1), the meaningful contribution criterion (Criterion 2), the fairness towards duty bearers criterion (Criterion 3). First, we argue that there is no relative democratic loss when courts get involved in the determination of climate mitigation policies (Criterion 1), at least if they do so by exercising strong judicial review. Second, we argue that if courts rely on human rights arguments to set certain emissions pathways, they would either set too loose requirements for national mitigation duties (and, thus, their contribution would not comply with Criterion 2) or they would set too stringent requirements for national mitigation duties (and, thus, their contribution would not comply with Criterion 3). Finally, we argue that if national courts relied on arguments that point to normative principles to which states should stick, they would comply with the aforementioned criteria. Thus, we argue national courts could contribute to climate justice in a fair way by relying on general principles of customary international and constitutional law to establish certain parameters for emissions reduction pathways that states should follow. Then, they could leave it to the legislative power to decide among the permissible pathways which one they should actually follow.