In 1989 the Exxon Valdez spilled 10.8 million gallons of crude oil into Alaska’s pristine Prince William Sound slathering wildlife and the untouched rocky shores with an inky, sticky coating of oil. The event created a powerful visual image of the sort of damage ocean ships can cause. A similar environmental disaster occurred in 2007, when 58,000 gallons of bunker fuel were spilled into San Francisco Bay after a container ship collided with the San Francisco-Oakland Bay Bridge in thick fog. California Governor Arnold Schwarzenegger declared a state of emergency.
But bad as those spills are, the shipping industry has an even more insidious side. Tankers and freight ships are polluting the air regularly, a problem with cumulative effects at least as onerous.
Experts, advocates and researchers are all urgently looking at ways to reduce the air pollution caused by ships, which is worsening as our global economy demands a constant exchange of goods from faraway places. Compared to the air pollution from cars and trucks, which is more stringently controlled and remains relatively flat, the pollution from ships is expected to more than double by the year 2030, according to the U.S. Environmental Protection Agency.
“Marine vessels are already a significant source of air pollution in the United States and their relative contribution is rapidly growing,” the EPA reported to the U.S. Senate in February.
The report states that ocean ships’ emissions in the U.S. alone measure about 13 percent of the nitrous oxide (N2O); 17 percent of the particulate matter and 50 percent of the sulfur oxide spewed into the air.
Of those, only the nitrous oxide is considered a true greenhouse gas because it becomes trapped by the earth’s atmophere and contributes to global warming. But the particulate matter and sulfur dioxide contribute to the dirty air that exacerbates asthma and other respiratory conditions.
The EPA anticipates that by 2030 these air pollution from ships will rise, comprising 46 percent of the nitrous oxide emitted; 52 percent of the particulate matter; and 95 percent of the sulfur oxide.
These emissions are a different composition from those of cars and coal plants, which are large emitters of carbon dioxide (CO2), the major greenhouse gas. But the N2O from ships makes them a significant culprit in the mix of polluters contributing global warming. (For more on greenhouse gas emissions see the EPA’s fact sheet.)
The pollution percentages from ships are rising fast as more produce and manufactured goods are being shipped globally, said John Kaltenstein, program manager (Clean Vessels Program) for Friends of the Earth, which was among the participants at the conference on ship pollution in Los Angeles in Feb. 25-27.