Low Carbon Transport: is It Achievable?

Low Carbon Transport: is It Achievable?


A Bristow, A D May, A Pridmore, M Tight, ITS, University of Leeds, UK



This paper reports results from a project funded by the Tyndall Centre for Climate Change Research exploring behavioural response and life style change in moving to low carbon transport futures. The project has four key aims to:

* Determine targets for CO2 reduction in the UK transport and sector and within this specifically for personal land based transport

* Develop strategies for personal land based transport to deliver said targets Explore the adaptation strategies of households in response to the measures identified above

* Identify policies that are both likely to move society toward a low carbon transport future and the most acceptable to households.

This paper reports on work completed with respect to the first two of these aims. The project focuses on personal land based transport as this area is the largest contributor to CO2 emissions within the UK transport sector and trends towards increased use of personal motorized transport how little signs of abatement. Moreover this is an area where the issue of behavioural change is perceived to be particularly intractable.

Climate change is an internationally recognized problem. The most recent Intergovernmental Panel on Climate Change (2001) state that: ?There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities? Thus far the Kyoto Protocol is the only international agreement under which developed countries commit to reduce greenhouse gas emissions by 5.2% by 2008-2010, though the treaty has yet to be ratified. In the absence of intervention greenhouse gas emissions will continue to increase and there is a reasonable degree of certainty that the climate will change as carbon concentrations in the atmosphere increase. In order to stabilize atmospheric concentrations at acceptable levels it will be necessary to reduce emissions.

The most common stabilization target in the literature is 550 ppm carbon dioxide. However, climate models suggest that stabilization at this level could still see global temperatures increase by more than 2 degrees centigrade, leading others to support stabilization at 450 ppm and even lower.

This paper explores the reductions that would be required in the UK to stabilize carbon dioxide concentrations in the atmosphere at 550 or 450 ppm using a ?contraction and convergence? approach that requires a greater commitment to reductions from developed countries than from developing countries. In order to reach the above stabilization levels the Royal Commission on Environmental Pollution estimates that UK emissions would have to reduce by approximately 60% and 80% respectively. Given total UK emissions of 148 MtC in 1997, emissions would have to reduce to 62.2 or 31.1 MtC respectively. The more stringent target is presently exceeded by emissions from the transport sector alone of 39 MtC. These are extremely challenging targets, even over the long term, especially for the transport sector, where emissions are still growing and the dependence on fossil fuels is almost total.

In considering appropriate reduction targets for transport a range of scenario building exercises in the UK were considered along with their views on the future role of transport as well as the National Road Traffic Forecasts. Over time the proportionate contribution of transport to CO2 emissions from transport has grown. There is no suggestion that this is likely to change in the future, and hence two possible future scenarios have been developed which portray proportionate contributions from transport of 26% (as now) or 41% (which allows the share of transport to increase in line with forecasts). These shares are then converted into MtC shares of the target emissions, giving targets ranging from 25.5 to 8.3 MtC respectively. Emission targets for personal land based transport would be in the range 15.3 to 5.0 MtC.

In order to examine how these targets might be achieved it was essential to gain a clear idea of the possible contribution of individual categories of measures, namely, technology, public transport, walking and cycling, restraint measures and land use. In the absence of any change, we estimate that emissions from personal land based transport will rise from 25 MtC to around 35 MtC by 2050. The role of technology and changes in purchasing behaviour to favour low emission vehicles was considered first, partly as this will form the base for further policy intervention. Two scenarios were considered to be feasible: firstly, that average emissions per vehicle fall by 25% by 2050, taking the ACEA/EU agreement to reduce average new car emissions as a starting point; secondly, a reduction of 60% in emissions per vehicle by 2050, achieved through additional improvements to petrol engines, changes in purchasing behaviour and some switching to alternative fuels. The 60% reduction scenario would just meet the least ambitious target. Further reductions from technology are possible (some such as the RAC Foundation are particularly optimistic) but these are not discussed here for three reasons. Even if a switch to hydrogen propulsion were achieved by 2050, (i) it is highly unlikely that this could be sourced from carbon neutral sources, (ii) sectors other than transport are likely to be able to reduce emissions further by adopting hydrogen power and (iii) on a life cycle basis, hydrogen vehicles at present do not offer a substantial reduction in CO2 emissions. It is therefore clear that behavioural change will be needed and an essential part of any strategy to achieve a low carbon transport future. Such behavioural changes could also facilitate early movement in the direction of the targets which is crucially important in order to prevent the build up of greenhouse gases in the atmosphere.

Estimates have been made of the contribution that could be expected from a range of different measures. So far the results suggest that even relatively strong assumptions on what could be achievable yield relatively small incremental changes in emission levels.

As an example, in order to meet the most stringent targets solely through, say fuel tax changes (in addition to technology gains) would require an annual increase in fuel price of approximately 8% from 2010 to 2050, also assuming the 25% decrease in average vehicle emissions (or approximately 5% assuming a 60% decrease in average vehicle emissions). It is essential to develop policy packages that can both achieve the targets and are acceptable to households. Consultation with experts as to the plausibility of our estimates is underway and results reported in the paper will reflect any changes as a result of this process, which will be completed in April 2003.


Association for European Transport