Shipping's Impact on the Air

Quick facts about the shipping industry:
• Ships consume at least 2 billion barrels of oil a year;
• They emit 20 percent of all sulphur dioxide emissions;
• 30 percent of all nitrogen oxide emissions;
• As much as 1.2 billion tons of carbon dioxide;
• Ships are responsible for at least 60,000 pollution-related deaths a year

Up until very recently, conventional wisdom held that shipping was a minor player in terms of greenhouse gas emissions. That all changed in October last year. Leaked details of a report by the International Association of Independent Tanker Owners (Intertanko) got into the press, and revealed an uncomfortable truth about the shipping industry -- its emissions could be double the amount everyone previously believed.

And that would make it's carbon footprint double that of the aviation industry.
The aviation industry emits around 650 million tons of greenhouse gases every year, representing around 3 percent of the global total.
If the leaked documents from research submitted for the Interanko report are to be believed, the shipping industry's contribution is more than twice the amount previously believed (600 million tons) -- which would mean ships emit as much as 1.2 billion tons of greenhouse gases a year.

source: http://edition.cnn.com/2008/WORLD/asiapcf/01/20/eco.about.ships/index.html?section=cnn_latest