The shipping industry and its regulators are drafting tentative pathways to reaching net-zero emissions by 2050. But the emission reduction efforts in the hard-to-decarbonize sector are slowed down by unclear regulation and uncertainty about which cleaner marine fuel would be the most cost-efficient and effective alternative to the oil-derived bunkering fuel that powers nearly all ships today. Emission Reduction Goals Last year, the United Nations agency, the International Maritime Organization (IMO), set out in its strategy indicative…