Transitioning global shipping to hydrogen fuel could prevent more than 129,000 premature deaths annually due to improved air quality. This is the conclusion reached by scientists from Nanyang Technological University in Singapore and the US National Centre for Atmospheric Research, who assessed the effects of maritime transport decarbonization.
The current global fleet annually consumes fuel equivalent to about 200 million tons of oil, accounting for about 2% of global energy‑related CO₂ emissions. However, ships emit not only carbon dioxide but also sulfur oxides, nitrogen oxides, particulate matter, and other pollutants that worsen air quality, especially in coastal areas and major ports. Despite the limits on sulfur content in marine fuel and nitrogen oxide emissions introduced by the International Maritime Organization, pollution from shipping still causes tens of thousands of premature deaths each year.
The researchers from Singapore decided to assess the effect of transitioning ships to hydrogen specifically in the context of human health. With this aim in view, they built a comprehensive model that combined emission calculations, atmospheric chemistry modelling, and data on the health impacts of air pollution. They took as a baseline the low‑carbon hydrogen production projects already announced to be accomplished by 2050, 88% of which is to be “green” hydrogen produced using renewable energy sources. They then considered two scenarios: a full transition of the global fleet to hydrogen and a partial option, in which half of the ships switch to the new fuel. The scientists took into account not only the near‑complete elimination of emissions from the ships themselves but also the pollution arising from hydrogen production.
The calculations showed that with a full transition, nitrogen oxide emissions from ships would decrease by 97%, sulfur dioxide by 51%, and hazardous fine particulate matter by 81%. As a result, the concentration of these particles would noticeably decrease in densely populated coastal areas of East and Southeast Asia, while ground‑level ozone along major shipping routes would fall by more than 20%. At the same time, in some regions where hydrogen production facilities are concentrated, emissions of certain pollutants would, on the contrary, increase, and in Eastern China and the Benelux countries, the reduction in nitrogen oxide emissions might even lead to a local increase in ozone concentration due to the specifics of atmospheric chemistry.
However overall, as the scientists calculated, a full transition of global shipping to hydrogen would prevent more than 129,000 premature deaths annually, while a partial transition would prevent nearly 53,000. Approximately three‑quarters of the lives saved would be due to reduced ground‑level ozone concentrations, while the remaining quarter would derive from reduced PM2.5 particulate concentrations. This is a rather unexpected result, as PM2.5 is usually considered the most dangerous pollutant to health. The greatest benefit from reduced particulate concentrations would be gained by East Asian countries, led by China, while the reduction in mortality due to lower ozone levels would be most pronounced in South Asia, especially in India.
There is also a financial dimension to this. According to the scientists’ estimates, the reduction in mortality from a full transition of marine shipping to hydrogen would bring about $284 billion annually to the global economy, while the cost of building a new hydrogen‑powered fleet is estimated at approximately $214 billion per year. Thus, the economic benefit from improved public health exceeds the cost of transitioning global shipping to hydrogen fuel.
