It’s no mystery that the shipping industry is a huge contributor to climate change, due to its carbon dioxide emissions and endless thirst for fuel. In an effort to limit that thirst, Shell Oil has devised a novel approach to fuel efficiency: air bubbles. The oil company installed a new system developed by London-based Silverstream Technologies on the hull of one of its ships, helping it move faster and more easily through the water. The technology relies on steel boxes welded to the ship’s hull and air compressors, which together create a layer of microbubbles between the vessel and the water. The result: 5% to 12% fuel savings. New international environmental regulations went into effect in January 2020. The United Nations’ International Maritime Organization now requires all international vessels except yachts to use fuels that contain no more than 0.5% sulfur—compared to 2019’s limit of 3.5%. Shipping and cruising vessels, including Carnival Cruise, Maersk, Norwegian Cruise Line, Grimaldi Group and Viking Lines, are adopting more energy-saving technologies, because the required cleaner fuel may inflate fuel costs by 30% to 60%—an estimated $30 billion annually. Meanwhile, the market for hybrid and electric boats is growing. The world’s first electric barges now chug between ports in Amsterdam and on the coast of Belgium. The vessels, made by Dutch company Port Liner, have been dubbed “Tesla ships.” Eventually, the hope is that these sorts of ships will also operate autonomously. Hybrid boats are making waves, too. Powered in part by solar energy, they reduce a watercraft’s weight, cut down on noise, boost passenger capacity and cut emissions.