The shipping industry has been trying to cut its carbon emissions for years, and with little to show for it. Nearly all of the world’s ship fleet still runs on diesel fuel, with about a quarter of new ships on order being built to run on somewhat lower-carbon alternatives like liquefied natural gas, methanol, or hybrid propulsion. The industry now faces serious pressure to pick up the pace. Shipping uses over 300 million tonnes of fossil fuels every year, producing 3 percent of greenhouse gas em...