As TreeHugger has noted here and here, transport by ship is not exactly CO2 free. According to the New York Times, the 90,000 ocean-going container ships, tankers and cruise ships emit more CO2 than all but the six largest polluting nations, equal to the amount emitted by all of the cars in the USA.
California Attorney General Jerry Brown, with environmental group Earthjustice, on behalf of the Center for Biological Diversity, Friends of the Earth and Oceana, have asked the Environmental Protection Agency to adopt standards for carbon dioxide. ''If the U.S. is to do its part in reducing the threat of global climate disruption, then EPA must limit the global warming emissions from ships that enter the ports of the United States,'' Brown said. The EPA has asked the UN to set international emissions standards, ''Pollution knows no political or geographical boundaries, and the EPA's current proposal to harmonize emissions standards at ports worldwide would deliver cleaner air to all Americans,''
EPA spokeswoman Jessica Emond said, continuing the EPA's current stance of regulating nothing and knowing that there is no way that an international agreement could be reached, since it would require higher grade, more expensive fuels, and who is going to pay for that? ::New York Times