Cruise Ships Are the Biggest Black Carbon Polluters

Larger ships make up the vast majority of black carbon emissions, with container ships, bulk carriers and oil tankers emitting 60 percent of all BC emissions, according to the 2021 European Maritime Transport Environmental report. Although cruise ships make up only 1 percent of the global fleet, they account for 6 percent of black carbon (BC) emissions. This reveals how disproportionately bad for the environment cruise ships are, releasing the highest amount of black carbon per ship of any vessel. Container ships, on the other hand, produce around a third of the black carbon per ship, at only 3.5 tonnes. But with so many of them (5008 according to the cited 2017 report, or 5,534 according to our latest stats), they have a far greater impact on the environment, accounting for 26 percent of the global fleet’s black carbon emissions.

Black carbon, or “soot” as it’s more commonly known, is created through the partial combustion of diesel, coal, or other biomass. When inhaled, the small particles can lead to health problems, namely with respiratory and cardiovascular illnesses. Yet it’s also an environmental hazard, as the dark color of its particles means that black carbon is very good at absorbing sunlight, which heats up the atmosphere and contributes to the climate emergency; something reflected in the report, which states that black carbon was responsible for 6.85 percent of the global warming contribution from shipping in 2018, while CO2 contributed 91.32 percent. This damage appears to be regional, as when soot blankets snow or ice, it reduces the natural ‘albedo’ effect - the ability to reflect sunlight - while heating up the surface, leading to greater melt, and more warming than elsewhere. This means black carbon near the Arctic is especially harmful.

As it stands, BC emissions are not currently directly regulated at an international level. The Arctic Council and the International Maritime Organization are, however, looking further into the impacts of black carbon in the Arctic. The report states that next steps may be to introduce a potential ban on the carriage and use of heavy fuel oil by ships in the Arctic, as of 2024.