Environmental Engineering Reference
In-Depth Information
Source:
Wang et al. (2007).
Figure 2.4
Global shipping network of routes and ports
quality, climate change, or other environmental impacts. Three critical questions for fore-
casting freight activity and environmental impacts include:
1.
Baseline conditions
: what are freight energy and activity patterns?
2.
Rates of change
: what are the forecast trends for these energy and activity patterns?
3.
Patterns of change
: where will future freight activity be located?
While interrelated, these questions are to some extent independent, given uncertainty.
Convergence is emerging on baseline estimates - at least in terms of major insights -
through academic dialogue about uncertainty ranges in oceangoing energy and emissions.
Freight transportation, particularly international cargoes, are an important and
increasing contributor to global and national economic growth, as well as regional eco-
nomic growth in and around major cargo ports. For example, international trade is
increasing as a proportion of US gross domestic product (GDP) - i.e. freight transporta-
tion is growing faster than US GDP (BEA, 2006; US Department of Transportation et
al., 2006). Economic activity related to imports and exports contributes about 22% of US
GDP in recent years, whereas goods movement contributed only about 10% of GDP in
the 1970s. Moreover, the dominance of containerized cargoes in seaborne trade suggests
that truck and containerized shipments may double by 2025 or sooner (Giuliano and
Godwin, 2006). This freight-sector growth rate in terms of dollar value is re
ected in the
observed ~6.3 to 7.2 percent annual growth rates of 'high-value' containerized trade
volumes, particularly from Asia (Vickerman, 2006). The US Bureau of Transportation
Statistics (BTS) recently released a report that describes North American freight activity
and trends (US Department of Transportation et al., 2006). This document reports
growth rates for North America above 7.4% for international trade and above 7.2% across
all measures of value.
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