This viewpoint states that the forecasting of energy-related CO2 emissions in the OECD countries, based on energy consumption, which uses the carbonization index as its indicator, is possibly incorrect. This paper argues that the forecasting of CO2 emissions should be based on GDP-the outcome of human activity and that it should use CO2 emission intensity as the indicator. The results of this analysis suggest that this would be more accurate. This viewpoint demonstrates the above proposition theoretically with the aid of statistical analysis and mathematical simulation. (c) 2004 Elsevier Ltd. All rights reserved.