This study aimed to determine the optimal CO2 reduction path for Jiangsu province to achieve the target of 40-45% reduction of CO2 emissions intensity by 2020 based on the 2005 level. Using the IPAT model combined with scenario analysis, we consider four parameters: economic growth, population growth, energy intensity and renewable-energy share. Each parameter is measured from different scenarios, and 54 kinds of scheme are set to forecast the CO2 emissions. The forecast results show that it is likely for Jiangsu province to achieve the target. Rapid economic growth is the main determinant that causes increase in CO2 emissions. Energy-intensity reduction and renewable-energy-share increase have beneficial influences on reducing CO2 emissions. The effect of energy-share increase is larger than that of energy-intensity reduction. As for the reduction of CO2 emissions intensity, energy-intensity reduction has a larger influence than renewable-energy-share increase. The optimal development mode until the year 2020 is as follows: the economy and population grow at appropriate rates, energy intensity reaches the level in developed countries, and the renewable-energy share increases to 15% in 2020. (C) 2013 Elsevier Ltd. All rights reserved.