CO2 emissions for shipping of goods

Globalization makes it easy to send goods around the world. The cost
for shipping goods has never been as low as now. However, the choice of
the means of transportation does severely influence the amount of CO2
emitted for the transportation of goods.
The following table shows the amount of CO2 (in grams) emitted per metric ton of freight and per km of transportation:
Air plane (air cargo), average Cargo B747
500 g
Modern lorry or truck
60 to 150 g
Modern train
30 to 100 g
Modern ship (sea freight)
10 to 40 g
Airship (Zeppelin, Cargolifter ) as planned 55 g
The values for air cargo has been taken from Lufthansa Air cargo, who operates a modern fleet. The world-wide average is probably higher because of the use of older plaines for air shipment. The effect of the CO2 emissions of airplanes are 2 to 3 times higher compared to the emissions on the ground, because airplanes release the CO2 in high altitudes into the atmosphere, where they do much more harm.
Conclusion: If you avoid air transportation, you help reducing the CO2 emissions!
Source of the values above: Klimaschutz und Flugverkehr On this page (in German) a lot of useful information about the CO2 emissions of aeroplanes can be found. Check it out!
ΞCarbon dioxide | Global warming