For the maritime sector, the postponement of the adoption of the Net Zero Framework has renewed attention to four structural issues that will determine the framework’s effectiveness (Fig. 1). First, additional technical work is required to establish robust default values for well-to-tank emissions and to strengthen the empirical foundations of the life cycle assessment guidelines2,5. Second, the global supply of zero and near-zero emission fuels remains far below projected demand, creating constraints that could delay early market formation6. Third, the design of the transition fund and the rules governing the use of carbon price revenues remain incomplete, particularly with respect to support for developing countries and least developed countries2. Fourth, the absence of incentives for early adopters weakens investment signals across emerging fuel and technology pathways2. These issues represent core challenges that the IMO’s Net Zero Framework must address for the maritime sector —but also with a view to standing in as a test case for aligning global action with the 1.5 °C objective.
a Data and benchmarks: Establishing robust empirical foundations for life cycle assessments and well-to-wake emission factors. b Clean fuel supply: Scaling global production and supply chains for zero- and near-zero-emission fuels. c Early adopters: Incentivizing first-movers through green shipping corridors and demonstration projects. d Carbon finance: Ensuring equitable fund allocation and supporting blue carbon ecosystems in developing nations. All panels illustrate the interconnected structural challenges required to align the maritime sector with the 1.5 °C Paris Goal.
The Sixth Assessment Synthesis Report of the Intergovernmental Panel on Climate Change explains that successful mitigation more generally depends on stable finance, strong institutions, rules that reduce participation costs, and mechanisms that foster trust across regions7. Reflecting these enabling conditions, the IMO’s Net Zero Framework must ensure predictable financial flows and provide broad access to emerging technologies. Certification systems must be transparent and credible. A share of carbon price revenues should support the conservation and restoration of blue carbon ecosystems in developing countries and least developed countries, managed through a separate accounting structure within the Net Zero Fund8. With these structural provisions in place, the framework can reduce emissions from shipping while also strengthening global clean fuel supply chains and supporting climate resilience. In doing so, it can serve as an effective instrument for aligning international action with the 1.5 °C objective2,7.