IMO’s (International Maritime Organization) sulfur regulation is less than ideal a Norwegian group pf academics suggest in a study, where an alternative to the existing and upcoming global sulphur cap is proposed.

The point of the study is that reducing the emission levels of sulphur oxides (Sox) and nitrogen oxides (NOx) has, on the perspective of human health, a positive impact. The goal of reducing these substances in the MARPOL Annex VI is mitigate the effect on global warning. However calculations from the study show that reducing SOx and NOx emissions, will increase the CO2 level to such a degree that it will contribute more to global warming, than at current emission levels.

Essentially the study finds that SOx has a short lived cooling effect, while CO2 lasts for millennia, thus burning high Sulphur fuel oil (HSFO) averaging sulfur content of 2,7% is climate neutral over a 100 year period, while the global sulphur cap of 0,5 % is over a 20 years period concluded to contribute to global warming.

The alternative to a global sulfur cap, the study suggests, could be to reduce Sox and Nox emissios in ECA (emissions control areas), ports and on coastal routes, but allowing ships to burn HSFO at open sea. In this way the impact of emissions on human health could be mitigated without increasing the CO2 level. 

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