How should international law respond to an unabated and continuing trend of environmental degradations? Even with the recent adoption and entry into force of the Paris Agreement, the climate change challenge is far from being resolved. Scientific findings have further underlined that pressures upon biodiversity persist and the international agreements in this area appear to have failed to put a halt to the decline in biodiversity. While concerns about limited effectiveness are probably as old (and unsettled) as the very idea of international environmental law, they have attracted renewed attention at the most recent United Nations (‘UN’) conference on matters of environment and development, the 2012 UN Conference on Sustainable Development (‘UNCSD’ or ‘Rio+20’). At UNCSD, which marked the 20th anniversary to the 1992 Rio Conference on Environment and Development (‘UNCED’), an academic idea for a novel legal concept entered the political stage that may either seem unpretentious and promising, or deeply troubling and simplistic. If the international community continuously fails to make sufficient progress in the environmental context, one may legitimately wonder whether the existing canon of environmental agreements and ‘principles’ is up to the challenge. Yet the Rio + 20 meeting did not only take place in the context of enduring environmental challenges. At the time of the conference, the consequences of the economic and financial crisis that shook many (but not only) European states and led them into severe ‘austerity’ programmes were far from being overcome. It is against this background of an economic, social and environmental crisis that suggestions for a novel kind of principle of environmental law were debated in the UNCSD context. And perhaps it is not a coincidence that the academic idea draws on the two areas of law that were probably affected the heaviest by the just-mentioned crises: Environmental law, struggling to come to terms with tremendous pressures put by the predominant economic model upon the natural surroundings, and human rights law seeking to fend off the worst impacts of austerity measures.