Reducing carbon emissions from personal road transport through the application of a Tradable Carbon Permit scheme: Empirical findings and policy implications from the UK Helen Harwatt Institute for Transport Studies, University of Leeds, 36-40 University Road, Leeds LS2 9JT, UK h.harwatt@its.leeds.ac.uk 1. I ntroduction Climate change is an urgent issue rapidly reaching the top of the political agenda. Greenhouse gases (GHG) are an essential component of the atmosphere as without them the earth would be uninhabitable. However, anthropogenic (human produced) GHG emissions are contributing to warming of the climate beyond what would be naturally expected. Carbon Dioxide (CO 2 ) is classified as the most significant GHG due to the quantity of release and quantity present in the atmosphere (IPCC, 2007). Based on the evidence available, the IPCC (2007) conclude with high confidence that anthropogenic warming over the last three decades has had a significant influence on many physical and biological systems. In addition, the I PCC (2007) have medium confidence regarding the anthropogenic influence on human systems. At its 33rd G8 summit in June 2007, the G8 agreed to aim to at least halve global CO 2 emissions by 2050 from current levels. However, binding figures were not set as the USA would only agree to such reductions if China and India were also included in the commitment (Elliot and Wintour, 2007). Whilst the G8 agreement is a major step forward in terms of climate change policy, recent scientific evidence suggests that in order to avoid going beyond a 2 °C increase in global temperature and thus avoid the most severe and irreversible climatic change, it would be necessary to reduce CO 2 emissions by 70% - 90% by 2050 (Bows et al ., 2006; Stern, 2006). The UK contributes 2% to global GHG emissions, of which the transport sector is responsible for 28% of CO 2 emissions and is forecast to increase in comparison to declines in other sectors (DEFRA, 2006a). Hence, whilst transportation is an intrinsic part of society and current lifestyles (Lyons et al., 2002; Anable, 2005), the transport sector makes a significant contribution to GHG emissions. For example, in the UK, road transport alone currently accounts for 26% of UK CO2 emissions, the majority resulting from personal use (DfT, 2006a). The UK government set out aims in the Energy White Paper (DTI, 2003) to achieve a 60% reduction of UK CO 2 emissions by 2050. This target is proposed to become legally binding, with a draft climate change bill outlining the necessary legislation (DEFRA, 2007). The UK government currently have a range of transport policies set out in the Climate Change Programme that are expected to deliver a reduction of CO 2 emissions from transport by 13% by 2010 from growth trends (in comparison to taking no action) (DEFRA, 2006b). Hence, whilst the measures are likely to have an impact on CO 2 emissions they will not deliver the significant reduction necessary in order for the UK to achieve a legally binding 60% reduction by 2050. Whilst it is possible that it may be more cost effective to reduce CO 2 emissions in other sectors, in consideration of the possible need to achieve a 90% reduction of UK carbon emissions (Bows et al., 2006), significant reductions from the transport sector are unavoidable. Thus, a new policy direction is essential. In recognition of the potential to deliver substantial carbon reductions with a high degree of confidence (DEFRA, 2006b; Roberts and Thumin, 2006), the 1