What scholars referred to as a climate change litigation ‘explosion’ in 2015 has today become an established movement which is unlikely to stop in the near future: worldwide, over a thousand lawsuits have been launched regarding responsibility for the dangers of climate change. Since the beginning of this trend in transnational climate litigation scholars have warned that the separation of powers is threatened where judges interfere with the politically hot issue of climate change. This article uses Jürgen Habermas's political theory on deliberative democracy to reconstruct the tension between law and politics generated by these lawsuits. This reconstruction affords a better understanding of the implications of climate change litigation: while the role of the judiciary as such remains unchanged, the trend is likely to influence the democratic legitimacy of judicial lawmaking on climate change, as it indicates an increasing realization that a sound environment is a constitutional value and is therefore a prerequisite for democracy.

On 9 October 2018, the Hague Court of Appeal confirmed the first instance judgement rendered in the world-famous Urgenda case: the Dutch State commits a tort by setting a goal for greenhouse gasses emissions reduction of only 20% by the end of 2020, compared to 1990 levels. The State is ordered to raise this goal to at least 25%. Both judgments are heavily criticised by constitutional and administrative law scholars. Most of this critique is ultimately linked to the objection that the Courts overstepped their task in the constitutional separation of powers. With this objection the State also takes the case to the Supreme Court.This annotation analyses the appellate court's decision step by step, pointing out where it differs from the lower court's decision and engaging with the various critiques. The Court of Appeal directly applies Articles 2 (right to life) and 8 (right to family life) of the ECHR, finds that these rights cover climate change related situations, and on the basis of Dutch civil procedure determines that 25% reduction is the factual minimum to prevent ECHR violations. Although parts of the decision could have been motivated in more detail, the authors conclude that the Court applied the law correctly and that neither the separation of powers, nor the political question doctrine were infringed.

On December 20, 2019, the Supreme Court of the Netherlands published its judgment in The State of the Netherlands v. Urgenda. The judgment is largely a discussion of questions of Dutch law, but contains several conclusions that are relevant from an international law perspective. In particular, the Court held that on the basis of the European Convention on Human Rights (ECHR), the Netherlands has a positive obligation to take measures for the prevention of climate change and that it was required to reduce its greenhouse gas (GHG) emissions by at least 25 percent by the end of 2020, compared with 1990 levels.

This article introduces four contributions to a special issue on ‘judicial law-making in European private law’, which seeks to reconstruct and understand (aspects of) the evolving transformative role of the judiciary in light of the interaction between the national and European level. The paradigmatic examples of climate change litigation and judicial dialogue in consumer mortgage cases show how courts are asked to address sensitive political questions in cases brought by private parties in civil proceedings. A ‘utopian’ (self-)understanding of the judicial task explains and justifies how and to what extent judges may address such societal problems through private law, and at the same time transform private law itself.