The Paris Target, Human Rights, and IPCC Weaknesses: Legal Arguments in Favour of Smaller Carbon Budgets

Abstract

The Paris Climate Agreement (PA) provides an overall target which limits global warming to “well below 2 °C above pre-industrial levels” and “pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels” (Art. 2 para. 1 PA). This article assesses the extent to which new insights can be derived from recent IPCC reports for the interpretation of Art. 2 para. 1 PA from a legal perspective. To this end, the article analyses the contributions of Working Groups I and III of the sixth assessment report. Methodologically, we compare the findings with previously published IPCC reports, namely the 1.5 °C report and the fifth assessment report. A legal interpretation of the Paris Agreement and of core concepts of human rights follows. Several empirical indications show that current global greenhouse gas budget calculations are quite generous. We provide five empirical arguments that clearly point in that direction. These empirical arguments, combined with legal arguments, demonstrate that the budgets must be smaller than those estimated by the IPCC. The legal arguments are based on Art. 2 of the Paris Agreement, as well as on human rights and the precautionary principle. These norms contain an obligation to minimise the risk of significant damage, i.e., to take rapid and drastic climate protection measures. This implies: 1.5 °C is the legally binding temperature target; adherence requires a very high probability of achieving the target; temperature overshoot and geoengineering tend to be prohibited, and budget calculations must be based on sceptical factual assumptions. These findings have also been confirmed by recent rulings of supreme courts, such as the ground-breaking climate decision of the German Federal Constitutional Court. The Paris Agreement and human rights underline a legally binding obligation for smaller global greenhouse gas budgets as those estimated in the greenhouse gas budgets of the IPCC—even compared to the 83 percent scenario in the latest assessment. Thus, climate policy will have to raise its ambitions towards zero fossil fuels and a drastic reduction of livestock farming in times of the Ukraine war.