Shipping, which transports 90 percent of the world’s globally traded goods, accounts for 3% of annual greenhouse gas emissions. This may not seem like much until you calculate that it amounts to more than 1.5 billion metric tons. (A full-grown elephant weighs about 1 metric ton.)

In other words, curbing ship emissions is essential in confronting the climate crisis. Fortunately, shipping companies seem to be getting on board. The International Maritime Organization has agreed to cut carbon emissions from global shipping by 50% by 2050 compared with 2008 levels — a good first step, but not enough to reach goals that will make a big difference. Going further, Maersk, the world’s biggest container shipper, is committed to making its fleet completely carbon-neutral by 2030, and is urging others to follow its lead. 

How do you transition away from diesel fuel? Shipbuilders have begun exploring ingenious solutions. They include rotors that provide wind power (ships currently fitted with these use up to 20% less diesel fuel), aerodynamic designs that turn a ship into a giant sail, powering vessels with hydrogen produced from seawater and covering decks with solar panels. Successful designs must provide enough power to propel these gigantic vessels through the water without taking up space needed for cargo.

Re-energizing the world’s cargo fleets will be expensive, but the time has come, says Diane Gilpin, CEO of the Smart Green Shipping Alliance. “I don’t think there’s any argument any longer about the need to do it. There is anxiety about which is the most appropriate way, because nobody wants to make a mistake. But you have to take a risk.”