The Oil Drum: Canada

The INDEPENDENT has done it again with the story "Shipping Pollution: Far More Damaging Than Flying". I recall their previous erroneous story about cows creating much more green house gases (GHG) than human activity.

This time the INDEPENDENT has picked up on a report that makes ocean going shipping to create creat more GHG than commercial aviation. The story does not mention the scientific fact that releasing GHG at high altitudes means aviation produces the equivilent of 2,600 billion tons of CO2 compared to the 1000 billion tons from ships. Also incorrect is the claim of ships using "bunker-C" heavy oil for fuel. Most ships except for the largest and oldest ships are propelled by diesel engines that burn no. 2 diesel. They could not burn the heavier high sulpher oil if they wanted.

Also the inference that big cities like Los Angeles has a large component of its air pollution from ships can't be correct. Five million cars and trucks traversing the LA highways pollute far more than the perhaps 100 ships that enter or layover at Santa Monica and Long Beach harbors. Besides, ships that are at dockside or at anchor don't pollute much because the propulsion engines are shut down. Only when they are moving at cruising speed do they emit large amounts of pollution (relative to dockside idling).

Lastly, lets look at the efficiency of shipping by air versus cargo/container ship. Aviation uses on the order of around 100 times more fuel per ton mile than ocean going ships, or produces about 400 times more GHG. Reducing the use of aviation would have the greatest effect on reducing inland pollution and GHG, the least effect on global trade & economies.

Mark in St Louis, USA