In the recent decades, most countries' CO2 intensity has decreased, but their decline rates are significantly different. Based on the data set of 89 countries from 1980 to 2008, this paper tries to quantitatively investigate the potential reasons for their differences, and discusses the possibility for developing countries to maintain a high carbon intensity reduction rate in the future as before. The econometric analysis implicate that (1) the decline rate of CO2 intensity in countries with high initial carbon intensity will be higher, which means CO2 intensity across the world has a significant convergence trend; and (2) keeping fast and steady economic growth can significantly help CO2 intensity decline, yet total carbon dioxide emissions will grow dramatically. Therefore, with the two objectives of intensity reduction and total amount control, carbon abatement policies need to weigh one against another. The results are robust to the initial year selection and country classification. (C) 2013 Elsevier Ltd. All rights reserved.