Transportation in a Climate-Constrained World

Abstract

A discussion of the opportunities and challenges involved mitigating greenhouse gas emissions from passenger travel. In the nineteenth century, horse transportation consumed vast amounts of land for hay production, and the intense traffic and ankle-deep manure created miserable living conditions in urban centers. The introduction of the horseless carriage solved many of these problems but has created others. Today another revolution in transportation seems overdue. Transportation consumes two-thirds of the world's petroleum and has become the largest contributor to global environmental change. Most of this increase in scale can be attributed to the strong desire for personal mobility that comes with economic growth. InTransportation in a Climate-Constrained World, the authors present the first integrated assessment of the factors affecting greenhouse gas (GHG) emissions from passenger transportation. They examine such topics as past and future travel demand; the influence of personal and business choices on passenger travel's climate impact; technologies and alternative fuels that may become available to mitigate GHG emissions from passenger transport; and policies that would promote a more sustainable transportation system. And most important, taking into account all of these options are taken together, they consider how to achieve a sustainable transportation system in the next thirty to fifty years.

Achieving deep reductions in US transport greenhouse gas emissions: Scenario analysis and policy implications

“…Lee et al (2001) estimate that if historical trends continue to persist into the future, energy intensities of new aircraft will be reduced 30-50% between 2000 and 2025 and that these levels will represent the fleet average by 2050. These significant reductions will require the widespread adoption of state-of-the-art aircraft technologies such as more efficient propulsion systems, advanced lightweight materials, and improved aerodynamics (e.g., winglets, increased wingspans), and potentially the adoption of even more advanced technologies-e.g., laminar flow control, unducted fan open-rotor engines, and improved air traffic control systems (IEA, 2008;Lee et al, 2001;Schäfer et al, 2009). Table 2 shows that total transport sector-wide energy intensity is reduced 45% between 1990 and 2050, and the average carbon intensity of all transportation fuels is about 2% lower than in 1990.…”

Avoiding carbon lock-in: Policy options for advancing structural change

“…Infrastructure investments can enable renewable energy use so that the misalignment across space and time is compensated for: grid extensions allow large scale transfers of electricity from generation sites to load sites. In the transport sector, substitution possibilities can also be mostly understood in terms of technology and infrastructure (Schäfer et al, 2009). However, consumer preferences are also important to determine the elasticity between carbon-intensive and low-carbon modes in the case of transportation, since mode choice also involves important trade-offs in terms of security, privacy, comfort and health as well as being driven by habituation to a single mode.…”

La voie étroite du « facteur 4 » dans le secteur des transports : quelles politiques publiques, pour quelles mobilités ?

“…Au contraire, l'avion et le TGV se développent parce qu'ils répondent à une élasticité vitesse/PIB que nous avons dans le scénario tendanciel évalué à 0,33 pour les voyageurs. Ce choix n'est pas anodin, il anticipe un mécanisme de saturation progressive des gains de vitesse [5]. Schäfer lui-même montre que pour que la mobilité continue à progresser selon les tendances passées (élasticité de valeur 1), il faudrait que dans quelques décennies la vitesse moyenne de déplacement quotidienne dépasse les 600 km/h.…”

“…Comme nous l'avons déjà indiqué, Pégase parvient « seulement » à diviser par deux les émis-sions (Sperling, et al 2009, entre autres, arrivent à des résul-tats semblables) [5].…”

“…Dans une perspective de modélisation, le couplage se traduit par une élasticité qui nous indique comment le trafic évolue quand le PIB varie. Pour les voyageurs, cette élasticité a été, dans les décennies passées, proche de la valeur 1, ce qui donne un parfait couplage entre croissance économique et mobilité [5,6]. La relation est encore plus nette pour les marchandises où l'élasticité entre les trafics (en tonnes-kilomètres) et le PIB a par exemple été supérieure à la valeur 1 au sein de l'Union Européenne [7].…”