We show that the energy intensity (energy/GDP) varies over a wider range and has had a greater impact on energy-related carbon emissions than the carbon factor (carbon/energy). Thus, in contrast to what is mentioned in Mielnik and Goldemberg (Energy Policy 27(5)(1999) 307-308) the energy intensity is an indicator which is as useful as, if not more useful than, the carbon factor to assess the evolution patterns of industrialized and developing countries regarding climate change. Some related data and study results are presented. (C) 2000 Elsevier Science Ltd. All rights reserved.