تغییرات معضل آب و هوا : فن آوری، تغییر اجتماعی و یا هر دو: بررسی گزینه های سیاست حمل و نقل در دراز مدت در ایالات متحده

Time is fast running out for formulating a viable global climate policy regime even as it seems obvious that the major initiative will have to come from the United States, which currently appears indisposed to take any meaningful action at all. This paper reviews the prospects for emissions reductions in the US passenger transport sector and the technical, economic, social, and political barriers to developing policies that focus solely on technology or pricing. Using scenarios it shows that, in order to meet stringent emissions targets over the coming half-century, technology and pricing policies may have to be supplemented by strategies to change life-styles and land uses in ways that effectively reduce car dependence. In the medium to long term, bold initiatives that treat vehicle users as citizens capable of shifting their interests and behaviour could form kernels of social change that in turn provide opportunities for removing many of the social and political constraints.

Since defecting from the Kyoto Protocol in 2001, the United States administration seems unwilling as well as politically unable to adopt genuine commitments to reduce greenhouse gas (GHG) emissions. In spite of several promising initiatives at local and state levels1, it appears obvious that a significant US climate policy agenda will not surface unless major changes start to occur within the domestic American political and cultural landscape. Indeed, the best way to interpret US recalcitrance on climate policy is that it is a product of several overlapping factors that go well beyond the disposition of the present Bush administration: an aggressive anti-mitigation lobby composed mainly of producers and marketers of energy-intensive goods and services (McFarland, 1984); a dominant social paradigm that places faith on material abundance, technology solutions and future prosperity (Dunlap and Liere, 1984); a relatively weak and divided polity whose policies are buffeted by short-term priorities (Skocpol, 1993)

All the scenarios discussed here for the passenger transport sector are merely illustrative and by no means predictions of how actual emissions will change in the long term. However, they provide important clues about the level of emissions reductions that are achievable under even ambitious programs and policies within the transport sector and provide indicative directions for further research. First, it is quite unlikely that US climate mitigation obligations could be met purely through technological and pricing policies, given the considerable technical, economic, social, and political barriers along the way. Even a hydrogen economy is not a panacea and may actually increase emissions, relative to other approaches involving efficiency and low-carbon fuels, unless determined efforts are made to generate zero-carbon hydrogen. Second, a series of programs that induce advanced technology commercialization as well as social change could potentially increase efficiency in vehicles, modes and land use, the last two implying a reduced reliance on personal vehicles. The emphasis of current climate change R&D should therefore be at least as much on social and cultural factors as on technology.