The last few years haven't been kind to the shipping industry. First there was the chaos of summer 2008, when the cost of oil rose to nearly $150 per barrel. Prices eventually dropped, but only because of the onset of the worst economic crisis since the Great Depression.
Today, things are looking up. Shipping has increased by a third since last year, and the amount of cargo coming into the U.S. is predicted to grow by nearly 20 percent this year, which would bring imports close to where they were in 2008.
But the future of transoceanic shipping is cloudy. Cargo ships use diesel that's cheaper to produce than jet fuel. And shipping goods over water is energy efficient; indeed, it's cheaper than any other method of long-distance cargo transport. But in the era of peak oil the problems facing the airline industry will also bedevil shipping companies.
Like planes, ships are too big to electrify — a pioneering solar-enhanced ship, for example, gets but 10 percent of its propulsion from electricity. Biofuels offer only a limited alternative to oil. Ships could move back to steam power, but burning coal is terrible for the environment and could soon be subject to international treaties (such as cap and trade) meant to limit carbon emissions.
Affordable air flight is an important spoke in the wheel of the global economy. But if oil depletion makes shipping steadily more expensive, the economic consequences are likely to be much more far-reaching than any contraction in the airline industry.