The ships that carry 90% of world trade (by volume) are a major source of air pollution:
Ships release more sulfur dioxide, a sooty pollutant associated with acid rain, than all of the world's cars, trucks and buses combined, according to a March study by the International Council on Clean Transportation. That study also found that ships produced an estimated 27% of the world's smog-causing nitrogen-oxide emissions in 2005. Only six countries in the world emitted more greenhouse gases -- which trap heat in the atmosphere, warming the globe -- than was produced collectively in 2001 by all ships larger than 100 tons, according to the study and United Nations statistics....
At current rates of growth, oceangoing ships will generate 53% of the particulates, 46% of the nitrogen oxides and more than 94% of the sulfur oxides emitted by all forms of transportation in the U.S. by 2030, the Environmental Protection Agency estimates. That compares with levels for the same pollutants in 2001 of 17%, 12% and 49%, respectively, according to the EPA.
Bruce Stanley reports on the issue in tomorrow's Wall Street Journal: Danger at Sea. Ships Draw Fire for Rising Role in Air Pollution (Nov 27).
These ships may be making an important contribution to global climate change, respiratory disease in ports where vessels are concentrated, and ocean acidification.
Individual cities, regional governments, and nations are adopting standards in their own waters:
Assertive governments and a few ports that wield substantial commercial power are proving that local action can reverberate internationally. Since Jan. 1, the state of California has required ships sailing within 24 miles of its shores to use cleaner-burning fuels in their auxiliary engines. Similar to a 2005 measure governing Europe's Baltic Sea region, the California law restricts access to America's two largest ports, Los Angeles and Long Beach. Ships that don't comply can be fined or impounded....
The prospect of authorities around the world adopting different standards for fuel and emissions worries many in the shipping industry. For commercial reasons, most ship owners and operators prefer burning less expensive, if dirtier, fuel when sailing outside a protected zone. Yet the procedures for switching back and forth between different types of fuel are complicated and potentially hazardous.
If a ship tries to switch between fuels that are incompatible -- a common risk -- waxes in bunker fuel can separate out like "curdles in milk" and clog fuel filters, says Martin Cresswell, director and fleet general manager at China Navigation Co., a shipping line headquartered in London. Lighter components in incompatible fuels can turn into gas and cause a "vapor lock" that stalls the engine. Mr. Cresswell's nightmare is a big ship adrift without power amid the towering swells of a Force 10 storm at the crowded entrance to the English Channel.
The risks and impracticality of switching fuels have persuaded two big shipping groups to seek a radical solution. Both the International Association of Independent Tanker Owners, or Intertanko, which represents 70% of the world's independent tanker fleet, and the Hong Kong Shipowners Association want the IMO [the UN's International Maritime Organization - Ben] to require ships to give up bunker fuel and use only distillates containing no more than 1% sulfur -- far below the current 4.5% IMO standard.
The International Bunker Industry Association calls any proposal to replace bunker with distillates impractical. Oil companies say that if ships burned only distilled fuel, refineries would need to process roughly 12 million additional barrels of crude oil daily -- more than the entire output of Saudi Arabia.
But Intertanko argues that if the IMO set a deadline for ships to adopt distillates, then refiners would have an incentive to invest in new capacity.
Other posts: Pollution from marine shipping (Nov 18); Environmentalists Petition EPA to Reduce Air Pollution from Shipping (Nov 19).