Some researchers have proposed that the drop in SO2 as a result of the IMO’s clean air regulations could be behind a recent spike in global sea surface temperature.
Carbon Brief analysis shows that the likely side-effect of the 2020 regulations to cut air pollution from shipping is to increase global temperatures by around 0.05C by 2050. This is equivalent to approximately two additional years of emissions.
Quoting some surprising paragraphs:
Not too much of a surprise. Sulfate aerosols are well known for causing cooling. The big issue with them is lung damage and acid rain