Omnibus versus Codification in EU Climate Law: Shipping, Aviation and the Legal Uncertainty of “Stop-the-Clock” Governance

Abstract This article argues that systematic legal codification provides a more resilient legislative architecture capable of stabilising regulatory expectations while preserving the EU’s constitutional legitimacy in the long-term governance of decarbonisation. It asks whether the EU’s increasing reliance on adaptive legislative techniques in transport decarbonisation undermines legal certainty and regulatory coherence in hard-to-abate sectors. Using a doctrinal and risk-governance analysis of EU climate legislation, the article focuses on shipping and aviation as regulatory stress tests for EU climate governance. Both sectors exhibit structural constraints, including technological rigidity, fuel fragmentation, and infrastructure dependency. In response, EU institutions have turned to adaptive techniques, namely legislative bundling across shipping and aviation, alongside omnibus simplification and “stop-the-clock” mechanisms. The article finds that their growing normalisation generates systemic governance risks, including weakened legal certainty, reduced legislative transparency, and constraints on effective judicial review. Tracing the shift from bundling under the “Fit for 55” package to post-2025 omnibus simplification, the article shows how these techniques decouple legal obligations from feasibility, preserving formal targets while undermining enforceability. The article concludes that systematic codification offers a more coherent and legally stable framework for governing long-term transport decarbonisation while preserving controlled flexibility through delegated and implementing measures.