Decoupling transport from economic growth: Extending the debate to include environmental and social externalities

The concept of decoupling embraces both immaterialisation and dematerialisation, by referring to the general delinking of environmental harm from economic production. This paper extends the theoretical debate and methodology on decoupling in transport to cover environmental (e.g. carbon) and social (e.g. fatalities) issues as well as the economic dimensions (e.g. income growth and transport activities). The typology developed here details the concepts of absolute and relative decoupling in a strong and weak version. This typology is then applied to explore the potential and the reality of transport decoupling in 15 major countries over the period since 1990, when concerns over the global environment and social issues have become a central part of the sustainable development agenda, through the measurement of changes in all three of the elements of sustainable development (economic, environmental and social). Two key transport externalities, carbon dioxide emissions and traffic fatalities, are studied, as these represent examples of environmental and social costs associated with increased levels of mobility. These 15 key countries included both developed and developing countries, and they together account for the majority of the global economy, carbon emissions and a substantial proportion of transport fatalities. The results show that decarbonisation of the transport sector has proved more difficult to achieve in the 15 countries over the 22years than the reduction in the levels of transport-related fatalities. Nevertheless, there is progress being made. Decoupling has taken place in both developed and developing countries, though the experiences vary in terms of timing (earlier vs more recent), consistency (stable vs variable), form (absolute vs relative) and magnitude (strong vs weak). Recoupling effects are limited. Transport has proved to be the most difficult sector to make more sustainable, as it is growing so fast and as it is necessary to support economies and lifestyles. Yet through combining measures of economic (e.g. income), environmental (e.g. carbon) and social (e.g. fatalities) wellbeing, it has been possible to identify positive trends in decoupling transport at the national level, as measured through relative decoupling. The much harder objective of an absolute decoupling is only just beginning to take place, but this must be seen as the primary objective in moving towards sustainability in the transport sector.