Transport systems meeting long-term climate targets : A backcasting approach

Sammanfattning: Future transport systems consistent with long-term climate targets are examined in this thesis, using a systems perspective covering the entire transport system. Aviation is given particular attention, as expansion of this mode is difficult to reconcile with climate targets. The aim is to provide scientific decision support for current transport policy-making, especi-ally regarding structures with high inertia, e.g. urban structure, roads, railways, fuel produc-tion systems and vehicle fleets. An additional aim is to widen the perception of possible transport futures consistent with meeting climate targets, and to support a wider discussion in society on this topic. Papers I and III are backcasting studies which encompass the whole transport system. Paper III outlines an image of future Swedish transport by 2050, in which energy use per capita is reduced by 60%. This reduction is consistent with a 42% reduction in total global greenhouse gas emissions. Paper IV shows that total air travel by Swedes generates about 8.7 million tons of CO2-equivalents annually. This corresponds to about 12% of total Swedish emissions. Considering the rapid growth in emissions, aviation is key to achieving overall climate targets. Paper V indicates that building high-speed tracks between Stockholm, Gothenburg and Malmö may yield emissions reductions of about 550,000 tons of CO2-equivalents annually, if a life-cycle perspective is considered for all modes. However, this reduction is contingent on continuing growth of transport volumes, which seems diffi-cult to reconcile with the images in Papers II and III. This might consequently be a „second best‟ solution if a more radical break in transport growth is deemed unlikely due to external drivers. The overall conclusion from this thesis is that improved vehicle technology and low carbon fuels are necessary, but not solely sufficient, to achieve long-term targets consistent with limiting global warming to two degrees. The growth in volume, especially of car and air travel and truck transport, must also be curbed. However, total travel volume can be maintained at 2005 levels if substantial modal shifts to cycling and public transport are achieved. Moreover, if conscious measures are taken regarding urban planning and the use of communications technology to replace travel, functional accessibility may increase considerably. The trend-breaking development needed to achieve climate targets requires a combination of different policy measures. Pricing of external effects, e.g. greenhouse gas emissions, is a key strategy and would involve ending aviation‟s exemption from carbon tax and value-added tax. Other possible pricing measures include differentiated charges for car travel in urban areas, km-charges on trucks and increased fuel taxes. However, to gain acceptance for pricing measures and maintain a well-functioning society, better alternatives with a lower climate impact are needed. Increased road capacity in urban areas usually increases car travel. Therefore, to achieve the targets set, strict prioritisation of investments in public transport, cycling and ICT infrastructure is needed, especially since public resources are limited. Another conclusion is that, for transport policies to be effective and not lead to sub-optimisations, it is necessary to consider the wider system delimitations explored in this thesis.