The big numbers in my recent posting are pretty incredible. So here's some extra data (mmm... data):

Firstly, the image I posted with the story is a bit misleading: it is a pretty dinky ship as far as container transport goes. A better example of the ships we're talking about would be the famous (or infamous) Emma Maersk, which is almost 400 metres long (if you walk, the movie will be over) and has a gross tonnage of 170,974. Saying that it's a big ship is an amazing understatement. The engine itself is 2,300 tonnes, and at maximum load it consumes 3.8 litres of fuel per second. The engines run continuously for power, and with crew changes most of these ships can operate 24/7.

Next, we need to talk about what makes these engines so dirty. Container ships consume something called "bunker fuel", which is a fairly generic term for any blend of low-quality fuel oils. During the oil refining process, higher-quality hydrocarbons like gasoline, propane, methane, etc are extracted, then heavier oils such as diesel and engine oil are removed. What's left over? Bunker fuel, and some even heavier solids which would be added to asphalt.

Bunker fuel is incredibly dirty, and burning it releases (literally) tons of pollutants into the air. Mentioning the carbon footprint in my last post was a bit misleading, as the majority of pollutants will be particulate matter, Sulphur Dioxide, and Nitrous Oxide, all of which are still very harmful to our atmosphere and environment at large. Automobiles, on the other hand, use cleaner fuel and have technologies like catalytic converters to minimize the impact of their exhaust (outside of Carbon emissions).

So saying that, worldwide, container ships have four times as big a Carbon footprint as automobiles? Perhaps no accurate. But the conclusion still stands: international container shipping has a terrible environmental impact, and needs to be minimized wherever possible.