How great the differences are between the individual transport modes can be demonstrated by way of example.
In this case, assume an all-truck journey between the container depot at Wőrth/Karlsruhe and Rotterdam, an overall distance of 574 kms. In Wőrth/Karlsruhe, the empty container is lifted to chassis by reach stacker (4 kg of CO2E) and transported 30 kms to the stuffing point at Graben Neudorf (22 kgs of CO2E). From Graben Neudorf, the laden container journey of 544 kms accounts for 479 kg of CO2E, so the total CO2E generated by the trip, prior to container unloading in the port, is 505 kg.
Now, for the same flow, truck the EC empty to Graben Neudorf and truck the FC back from there to the Wőrth/Karlsruhe trimodal terminal. That round trip generates a total of 52 kg. At the railhead, handling by reach stacker of the laden container adds 8 kg. Onward rail transport to Rotterdam (667 kms) generates 233 kg of CO2E. At Rotterdam, the total footprint is 293 kg, a saving of 212 kg.
Finally, instead of rail from Wőrth/Karlsruhe, ship by barge. The barge leg over 653 kms is 111 kg, so the total for the whole trip is 171 kig, an overall saving of 334 kg.
The IMTIS calculations can be made for any number of seaports and inland points,
As Contargo points out, COP21 in Paris resolved to keep global warming up to the year 2100 below 2deg C. In order to achieve this objective, CO2E in Europe are to be reduced by 40% by 2030. If this is to succeed, emissions in the area of transport will have to be substantially reduced.