Lee Stapleton

Estimating direct rebound effects for personal automotive travel in Great Britain

Direct rebound effects result from increased consumption of cheaper energy services. For example, more fuel-efficient cars encourage more car travel. This study is the first to quantify this effect for personal automotive travel in Great Britain. We use aggregate time-series data on transport activity, fuel consumption and other relevant variables over the period 1970-2011 and estimate the direct rebound effect from the elasticity of vehicle kilometres with respect to: a) vehicle fuel efficiency (km/MJ); b) the fuel cost of driving (£/km); and c) road fuel prices (£/MJ). We estimate a total of 54 models, paying careful attention to methodological issues and model diagnostics. Taking changes in fuel efficiency as the explanatory variable, we find no evidence of a long-run direct rebound effect in Great Britain over this period. However, taking changes in either the fuel cost of driving or fuel prices as the explanatory variable we estimate a direct rebound effect in the range 10% to 27% with a mean of 18%. This estimate is consistent with the results of US studies and suggests that one fifth of the potential fuel savings from improved car fuel efficiency may have been eroded through increased driving. We also show how the normalisation of distance travelled (per capita, per adult or per driver) affects the results obtained.

Assessment of Multifunctionality and Jointness of Production

Multifunctionality is one way to reconcile agriculture with sustainable development: agriculture, beyond the production of food and fibre, also provides important social, environmental and economic functions to society. In general, much of the current literature on agricultural multifunctionality is qualitative and narrative, and focuses on demonstrating the existence of social and/or environmental functions. In this chapter, we start with the existence of these multiple functions and we seek to measure the relationships between them through the design of indicators of multifunctionality. We present a structured sequential framework to guide the development of multifunctionality indicators based on the concept of joint production. The three stages articulated in this framework are: Identification of jointness. Qualitative assessment of jointness. Quantitative assessment of jointness.