River and canal shipping's carbon footprint is far larger than previously understood, with inland vessels generating nearly a quarter of global shipping's CO₂ emissions in 2022, according to Splash247.
Splash247 reported that a new study published in Nature Climate Change estimates inland vessels emitted around 164m tonnes of CO₂ in 2022 — equivalent to 24.7% of total shipping emissions that year. The finding is striking because navigable rivers and canals account for less than 1% of the world's navigable waterways.
Closing the tracking gap
Unlike oceangoing shipping, where AIS (Automatic Identification System) data, fuel consumption and emissions have been extensively analysed, no detailed global inventory previously existed for vessels operating across the world's rivers and canals, according to Splash247. Researchers in China sought to close that gap by analysing approximately 20bn vessel-tracking records between 2019 and 2022, identifying persistent vessel activity across 12,289 navigable rivers and canals.
Calculating emissions was not straightforward. AIS reception is patchy on many inland waterways, and conventional vessel-tracking systems draw straight lines between position reports, producing unrealistic routes across land when ships navigate winding rivers. The researchers therefore developed a route-reconstruction model to follow actual river geography before combining vessel movements with ship specifications to estimate fuel consumption and emissions, Splash247 reported.
Where inland shipping emissions are concentrated
The resulting picture is highly concentrated. Around 69% of inland shipping emissions came from just 20 major rivers, including the Yangtze, Rhine, Mississippi and Danube; cargo vessels accounted for approximately two-thirds of the total, according to Splash247.
| Metric | Value |
|---|---|
| Estimated inland vessel CO₂ emissions, 2022 | 164m tonnes |
| Share of global shipping emissions | 24.7% |
| Navigable rivers and canals as a share of world's navigable waterways | Less than 1% |
| Share of inland emissions from 20 major rivers | 69% |
| Share of inland emissions from cargo vessels | Roughly two-thirds |
| Change in inland vessel emissions, 2019–2022 | Nearly doubled |
More concerning is the trajectory, Splash247 reported: inland vessel emissions nearly doubled between 2019 and 2022, with rising vessel activity and economic demand, particularly in Asia, identified as the principal drivers. The study also finds emissions varying substantially with seasons, water conditions and climate, reflecting the interaction between cargo demand and the physical capacity of rivers to accommodate shipping.
What the study means for shippers and operators
Inland navigation is frequently promoted as a lower-carbon alternative to road freight, particularly in Europe and China, according to Splash247. The new research does not overturn that argument on a tonne-mile basis, but it does expose a substantial part of shipping's carbon footprint that has historically received comparatively little attention.
Splash247 noted that inland shipping is hit from an emissions point of view by economies of scale: oceangoing ships tend to be far larger, so they carry more cargo for less noxious output. Ironically, however, it is on rivers where many of the most pioneering green shipping initiatives are underway over the past decade.
Ultimately, the study does not remove inland shipping's tonne-mile advantage over road freight, but it does identify where the largest share of that advantage is offset by absolute emissions. With 20 rivers responsible for 69% of the category's CO₂ output and emissions nearly doubling in three years, the hidden carbon bill of river shipping is now quantified for operators to see.
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