The Doubtful Environmental Benefit of Reduced Maximum Sulfur Limit in International Shipping Fuel

On January 1st, 2012, the maximum limit for sulfur concentration in marine fuels on the high seas was lowered from 4.50% to 3.50% by the International Maritime Organization (IMO). It was one of a series of planned steps toward reducing the negative environmental and health impacts of international shipping. This study investigates the effectiveness of the IMO regulation in reducing global sulfur emissions. We found a reduction in global average sulfur concentration of only 0.07% points from 2011 to 2012. On the positive side, we also found that only 2.3% of the bunkerings were noncompliant in 2012, that is, exceeded the new 3.50% sulfur concentration cap. The analysis furthermore suggests that compliance with the new regulation is achieved by blending high sulfur fuel with lower sulfur fuel, rather than by removing high sulfur fuel from the market or removing the excess sulfur. The main conclusion is that the regulation has been effective in reducing the maximum sulfur concentration but has not been very ...