Ecological footprint inequality across countries: The role of environment intensity, income and interaction effects

Recently, White (2007) analysed the international inequalities in ecological footprints per capita (EF hereafter) based on a two-factor decomposition of an index from the Atkinson family (Atkinson, 1970). Specifically, this paper evaluated the separate role of environment intensity (EF/GDP) and average income as explanatory factors for these global inequalities. However, in addition to other comments on their appeal, this decomposition suffers from the serious limitation of the omission of the role exerted by probable factorial correlation (York et al., 2005). This paper proposes, by way of an alternative, a decomposition of a conceptually similar index like Theil's (1967) which, in effect, permits clear decomposition in terms of the role of both factors plus an inter-factor correlation, in line with Duro and Padilla (2006). This decomposition might, in turn, be extended to group inequality components (Shorrocks, 1980), an analysis that cannot be conducted in the case of the Atkinson indices. The proposed methodology is implemented empirically with the aim of analysing the international inequalities in EF per capita for the 1980–2007 period and, amongst other results, we find that, indeed, the interactive component explains, to a significant extent, the apparent pattern of stability observed in overall international inequalities.