Those sulphur emissions were not large by atmospheric standards (the entire shipping industry “only” emits about 800 Mt of CO2 a year, not all of which even com

Those sulphur emissions were not large by atmospheric standards (the entire shipping industry “only” emits about 800 Mt of CO2 a year, not all of which even comes from high-sulphur bunker fuel). However the SO2 quantity does have severe environmental impact (the first emissions trading scheme, back in the 90s, was to control SO2 emissions), in this case increasing the acidity of the oceans and coastal regions thanks to so-called acid rain. The real tragedy is that the scrubbers remove the SO2 from the exhaust and…deposit it in the ocean.