Toward zero emissions: the shipping sector in transitionIn April 2018, the International Maritime Organization (IMO) set an objective to reduce absolute GHG emissions from shipping by at least 50% by 2050 compared with a 2008 baseline. To achieve this target and ultimately progress towards carbon neutrality in the sector by mid-century, in line with Intergovernmental Panel on Climate Change (IPCC) scenarios to limit the rise in global temperature to 1.5°C, shipping will need to go beyond operational and energy eﬃciency and deploy zero-emission fuels and propulsion technologies. Given the 20-30-year lifetime of vessels and other industry assets, the maritime sector must therefore ensure that zero-emission vessels are operating on a commercial scale on deep-sea trade routes by 2030. An analysis for the Getting to Zero Coalition estimated that achieving long-term decarbonization objectives would require that zero-emission fuels make up 5% of the international fuel mix by that point.1 To reach these objectives, accelerating investments in zero-emission fuels and technologies will be crucial.The decarbonization of shipping is fundamentally interlinked with the land-based transition to renewable sources of primary energy and particularly to the adoption of hydrogen as an energy carrier. The decarbonization of shipping depends on the availability of green hydrogen; conversely, the scaling up of land-based green hydrogen production will not happen without reliable, large sources of demand and the construction of associated electricity generation and hydrogen production and storage infrastructure. The adoption of green ammonia as a fuel for international shipping may be the most promising route to decarbonizing the most challenging segments of the industry. By accelerating its own deployment of ammonia-powered vessels, shipping can act as enabler for the wider decarbonization of the world’s energy usage.