The world is ticking down to a deadline that promises to have major ramifications in the global fuel markets. On January 1, 2020, the International Maritime Organization (IMO) will require the sulfur content in marine fuel to drop from a maximum of 3.5 percent down to 0.5 percent. The rule is meant to curb pollution from ships. Combustion of high-sulfur fuels leads to the production of compounds like sulfur dioxide, which causes respiratory problems and produces acid rain. This rule continues a trend of limiting the sulfur content in fuels (which originates from the sulfur contained in crude oil). Europe began tightening sulfur specifications in the 1990s, and the U.S. began to phase in ultra-low-sulfur diesel (ULSD) in 2006. Prior to implementation of the ULSD standard in the U.S., gasoline often traded at a premium to diesel. But meeting the ULSD standards required refineries to invest billions of dollars […]