On March 5, 2026, the CETA Joint Committee adopted a binding Joint Interpretation clarifying that non-discriminatory measures taken to protect the environment or combat climate change do not constitute a breach of Article 8.10 (Fair and Equitable Treatment) or Annex 8-A (Indirect Expropriation) of CETA. The interpretation is legally binding on CETA tribunals and was confirmed by the CETA institutional bodies. This demonstrates how states can ‘modernise’ existing treaties in real time without the political cost of full renegotiation. By issuing a binding joint interpretation, Canada and the EU have created a legal shield for environmental regulation, ensuring it remains a sovereign right rather than a compensable interference with investment. This approach significantly reduces the risk of regulatory chill and could serve as a template for other treaty parties seeking to recalibrate ageing investment agreements.