ipcc_wg3_ar5_final-draft_postplenary_chapter8

Final Draft Chapter 8 IPCC WGIII AR5
Piecyk, 2012) whereas many smaller freight operators have yet to act (Oberhofer and Fürst,
2012).
8.4 Infrastructure and systemic perspectives
Transport modes, their infrastructures, and their associated urban fabric form a system that has
evolved into the cities and regions with which we are most familiar. ‘Walking cities’ existed for 8000
years; some are being reclaimed around their walkability (Gehl, 2011). ‘Transit cities’ were built and
developed around trams, trolley buses, and train systems since the mid 19th century (Cervero, 1998;
Newman and Kenworthy, 1999). ‘Automobile cities’ evolved from the advent of cheap LDVs
(Brueckner, 2000) and have become the dominant paradigm since the 1950s, leading to automobile
dependence and auto‐mobility (Urry, 2007). A region can be defined and understood in terms of
the transport links to ports and airports regardless of the number and types of cities located there.
In all cases, the inter‐linkages between transport infrastructure and the built environment establish
path dependencies, which inform long‐term transport‐related mitigation options. For a general
discussion of urban form and infrastructure see Chapter 12.4.
8.4.1 Path dependencies of infrastructure and GHG emission impacts
Systemic change tends to be slow and needs to address path dependencies embedded in sunk costs,
high investment levels, and cultural patterns. Technological and behavioural change can either adapt
to existing infrastructures, or develop from newly constructed infrastructures, which could provide
an initial template for low carbon technologies and behaviour. Developments designed to improve
infrastructure in rapidly urbanizing developing countries will decisively determine the future energy
intensity of transport and concomitant emissions (Lefèvre, 2009), and will require policies and
actions to avoid lock‐in.
The construction, operation, maintenance, and eventual disposal of transport infrastructure (such as
rail tracks, highways, ports, and airports), all result in GHG emissions. These infrastructure‐related
emissions are usually accounted for in the industry and building sectors. However, full accounting of
life cycle assessment (LCA) emissions from a transport‐perspective requires these infrastructurerelated
emissions to be included along with those from vehicles and fuels (see Section 8.3.5). GHG
emissions per passenger‐kilometre (p‐km) or per tonne‐kilometre (t‐km) depend, inter alia, on the
intensity of use of the infrastructure and the share of tunnels, bridges, runways, etc. (Åkerman,
2011; Chang and Kendall, 2011; UIC, 2012). In the United States, GHG emissions from infrastructure
built for LDVs, buses, and air transport amount to 17–45 g/p‐km, 3–17 g/p‐km, and 5–9 g/p‐km
respectively (Chester and Horvath, 2009) with rail typically between 3–11 g/p‐km (see Table 8.1).
Other than for rail, relevant regional infrastructure‐related GHG emissions research on this topic is
very preliminary.
Opportunities exist to substantially reduce these infrastructure related emissions, for instance by up
to 40% in rail (Milford and Allwood, 2010), by the increased deployment of low‐carbon materials and
recycling of rail track materials at their end‐of‐life (Network Rail, 2009; Du and Karoumi, 2012).
When rail systems achieve modal shift from road vehicles, emissions from the rail infrastructure may
be partially offset by reduced emissions from road infrastructures (Åkerman, 2011). To be policyrelevant,
LCA calculations that include infrastructure need to be contextualized with systemic effects
such as modal shifts (see Sections 8.4.2.3 and 8.4.2.4).
24 of 115