Little more than 2 1/2 years from now, the global fleet of merchant ships will have to reduce drastically how much sulfur their engines belch into the atmosphere. While that will do good things — like diminishing the threat of acid rain and helping asthma sufferers — there’s a $60 billion sting in the tail. That’s how much more seaborne vessels may be forced to spend each year on higher-quality fuel to comply with new emission rules that start in 2020, consultant Wood Mackenzie Ltd. estimates. For an industry that hauls everything from oil to steel to coal, higher operating costs will compound the financial strain on cash-strapped ship owners, whose vessels earn an average of 70 percent less than they did just before the 2008-09 recession. The consequences may reach beyond the 90,000-ship merchant fleet, which handles about 90 percent of global trade. Possible confusion over which carriers […]