Fascinating and important decision by the German Constitutional Court on climate change. A few quick thoughts from an IL/IR perspective https://www.nytimes.com/2021/04/29/world/europe/germany-high-court-climate-change-youth.html

First, IPCC reports/estimates and Paris agreement targets are cited throughout as defining what the government should achieve (as they were in court decisions in other countries). Never say again that these bodies don't have legal consequences https://www.bundesverfassungsgericht.de/SharedDocs/Pressemitteilungen/EN/2021/bvg21-031.html

Second, the case hinges on the recognition that climate change infringes on fundamental rights but especially that if the government doesn't act strongly enough now then future governments will have to limit freedoms in unacceptable ways in order to mitigate climate change..

"if much of the CO2 budget were already depleted by 2030, there would be a heightened risk of serious losses of freedom because there would then be a shorter timeframe [..] to make the transition to climate-neutral behaviour in a way that respects freedom."

"However, since the current provisions on allowable emission amounts have now already established a path to future burdens on freedom, the impacts on future freedom must be proportionate from today’s perspective."

"the objective duty of protection [..] encompasses the necessity to treat the natural foundations of life with such care and to leave them in such condition that future generations who wish to continue preserving these foundations are not forced to engage in radical abstinence."

Finally, there is very little specifically German about the laws on which this case was based. Most countries (certainly in Europe) guarantee the same fundamental rights and we have seen similar successful lawsuits elsewhere (e.g. the Netherlands). Who will be next?