This could be the ECJ’s best opportunity to speak on the EU’s climate mitigation obligations under European and international law. In particular, I argue that the agreement is incompatible with the EU’s mitigation obligations. Together, the three advisory opinions and the ruling of the ECtHR shape our understanding of States’ climate obligations. The “opinion perspective” is well-suited to address climate mitigation obligations – as we have seen in ITLOS, the IACtHR, and the ICJ’s opinions. Another aspect of the EU-Mercosur Deal that has been criticised for its potential to increase the EU’s emissions and undermine climate policies is the rebalancing mechanism.