Environmental Engineering Reference
In-Depth Information
(a)
(b)
Source:
Skjølsvik et al. (2000).
Figure 2.1
Ocean shipping (a) as a substitute and (b) as a complement to other freight
modes
freight (inland river and shortsea combined) is second in mode share, moving about 40-44
percent of the cargo tkm in recent years (Mantzos and Capros, 2006; ECDGET and
Eurostat, 2006); in the USA, rail freight tkm is nearly equal to road freight. Moreover,
these mode-share summaries ignore the 46 000 giga-tkm (one Gtkm
10
9
tkm) of
seaborne trade moving cargoes among all trading nations from distances outside the
domains from which national statistics are reported. For context, seaborne trade is some
30 times greater than the seaborne mode share in the EU, and 12 times greater than all
freight tkm in the EU. Figure 2.2 summarizes these mode-share comparisons.
Categorizing environmental impacts of ocean shipping
Environmental impacts from ocean shipping can be summarized in di
erent contexts. For this
overview, the impacts are categorized as either episodic or routine. These designations help to
explain why some aspects of ocean shipping, such as stack emissions, are so challenging to
address. Example environmental impacts under this taxonomy are listed in Table 2.1. Some
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