By halving its top cruising speed over the last two years, Maersk cut fuel consumption on major routes by as much as 30 percent, greatly reducing costs. But the company also achieved an equal cut in the ships’ emissions of greenhouse gases. “The previous focus has been on ‘What will it cost?’ and ‘Get it to me as fast as possible,’ ” said a Maersk spokesperson. “But now there is a third dimension. What’s the CO2 footprint?”
Slowing down from high speeds reduces emissions because it reduces drag and friction as ships plow through the water. Carriers from Germany to Israel to China are starting to embrace the slow strategy. Today more than 220 vessels are practicing “slow steaming” — cruising at 20 knots on open water instead of the standard 24 or 25 — or, like Maersk’s vessels, “super slow steaming” (12 knots).