The rules, set roughly a decade ago through the International Maritime Organization, an arm of the United Nations, take effect on Jan. 1, 2020, and aim to slash the amount of sulfur in marine fuel for oceangoing ships. The International Energy Agency, which advises governments on energy policies, has warned that the measures—by banning cheap energy sources and requiring ships to run on premium fuels—could cause a surge in demand for specific fuels that ripples across commodity markets and affects prices for crude, diesel and other petroleum products. International oil prices have recently surged above $80 a barrel and some predict $100 is possible, driven by a reinstated U.S. ban on Iran oil exports and dwindling spare capacity among members of the Organization of the Petroleum Exporting Countries. The new maritime demand is expected to tighten supplies further, especially for low-sulfur diesel but also in oil markets more broadly. […]