"People on the Move": Human Factors and Carbon-Dioxide in Industrialized Countries

Lee Schipper, Lawrence Berkeley Laboratory

Abstract

We introduce the notion of transportation externalities, noting that in many authoritative national studies these are not seriously internalized according to their likely range of marginal social costs. CO2 emissions are seen as a small problem today compared with other transport externalities. We review trends in car ownership, mobility, characteristics, and fuel economy in IEA countries from the early 1970s to the mid-1990s. Except in the US through the early 1990s, these factors changed towards higher fuel consumption per capita and higher CO2 emissions. We also find that the share of total travel provided by cars and air travel increased virtually everywhere. We show how each contributed to changes in CO2 emissions.

Technical efficiency of cars improved markedly, feeding larger size and greater performance in Europe, and boosting these in the US after the early 1980s. Thus factors increasing emissions were principally behavioral factors, and, except in the US, these were stronger than the technological factors restraining emissions. Noting that both incomes and real fuel prices are powerful determinants of this evolution, we credit the CAFE standards in the US for some of the large reduction in fuel use/km in cars, or fuel use/capita relative to incomes per capita there. We close speculating over options to restrain future emissions, concluding, as do many national studies, that only broad transportation policy reforms that hit at all of the externalities in transportation could support genuine restraint in CO2 emissions from travel.