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Ponderous Polluters Let a Little Light Shine in

A cargo ship that generates some of its power from the sun may shine a light on ways to reduce transportation's dirty little secret — the world's oil-powered fleets are hideous global warmers.
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Driving a Prius down the highway and passing those gas-guzzling SUVs gives a sense of greenness that owning an automobile has never provided before. Those who install SunTech solar panels or other brands from overseas enjoy a similar pride in their commitment for a cleaner world; they feel greener than those bare-roofed people next door. Knowing of the cloud of emissions pouring from the smokestacks of the container ships that brought these commodities to their doorstep might give them second thoughts.

But they shouldn't feel too bamboozled. When negotiating the Kyoto Protocol, climate change experts intuitively thought that the 90,000 ships plying the seas contributed but a miniscule amount of global warming gases compared to the world's 760 million cars. Dismissing shipping as trivial to global warming, no one considered reducing its carbon footprint while negotiating the agreement.

New research though tells a different story, revealing that sea trade contributes nearly 40 percent as much carbon dioxide to the atmosphere as do automobiles. It dwarfs their sulfur dioxide emissions. Currently, ships burn a sludge-like fuel that has a sulfur content as high as 27,000 parts per million, while fuel in the United States used by cars and trucks contains no higher than 15 parts per million.

Vehicles only out-pollute ships when it comes to nitrogen oxides — and not by very much. Worse, 50 percent of ships' particulate emissions are sooty black carbon, which has 60 percent of the warming effect of carbon dioxide.

Furthermore, as more and more of the Arctic ice melts away, shipping lanes may move further north, bringing pollution with them. Soot emitted by ships in this region would blacken a goodly portion of the remaining ice. The dark ice would lose it solar reflectivity. It would therefore absorb sunlight and emit solar heat instead, causing the earth to warm even faster.

Mix the present danger with ever increasing ship traffic due to the rise of world trade with China, and many experts expect shipping will soon account for 40 percent of the world's air pollution. The fact that 70 percent of ship traffic occurs within 250 miles of coastline has caused authorities in the United States to take action. Responding to recent studies that show the human cost of pollution from ships — 60,000 extra deaths per year worldwide and costing more than $300 billion annually in health expenditures due to pulmonary and cardiovascular diseases — the U.S. government has proposed a 230-mile clean-air exclusion zone around both coasts. Only ships that burned cleaner fuels and adopted emission control technologies could enter.

Such strong demand for cleaner ships has led, for example, to the construction of the world's first solar-powered cargo ship, the MW Auriga Leader, which just visited the Port of Long Beach on its maiden voyage.

Its 328 solar panels placed on the ship's deck help power the vessel's main electrical grid while at sea and in port. They provide up to 10 percent of the ship's power and reduce fuel consumption by 6.5 percent. The Auriga Leader was built for Nippon Yusen K.K., Japan's largest shipping line. A car carrier, the ship's cargo consisted of 6,400 Priuses. Nippon Yusen and Toyota installed the panels as a demonstration project to draw attention to reducing diesel emissions from large ships.

If the experiment succeeds, others will follow suit, leading to the widespread solarization of the world's fleets. Hybrid ships could significantly scale down the amount of pollution currently produced. Nippon Yusen hopes to halve its emissions and fuel consumption by next year. Perhaps not far in the future clean cars and solar panels will be delivered by clean running, possibly solar-powered ships, and the idea of free trade will include clean trade.

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