In order to avoid dangerous climate change, the Intergovernmental Panel on Climate Change has suggested that the increase in global temperature should be limited to under 2°C by the end of this century. In response to this objective, many countries have set up varied mitigation targets for CO2 emissions, which reflect their own specific situations. In this article, scenarios for CO2 emissions up to 2050 are set up for three representative countries: the United States of America, France and China. We compare these scenarios to Business-as-Usual scenarios in the framework of a sectoral-emission model. This model establishes the feasibility of the scenarios and targets, by dividing emissions into three main sectors: the power sector, the transport sector and others. The model, based on STIRPAT modeling and Support Vector Regressions, includes three major types of technical improvements: hybrid vehicles, energy-structure changes and energy-efficiency improvements. Governmental targets prove to be stricter than the 2°C scenario for the US and France, while the governmental target for China is more tolerant than the 2°C scenario, taking economic development into account. The article also shows that the energy mix could remain unchanged for electricity production with the implementation of Carbon Capture and Storage technology in order to hit the government target in China, and the 2°C objective in the US. Otherwise, these countries would have to reduce their share of coal in the energy mix to under 20%. In the meantime, half of traditional vehicles should be replaced by hybrid vehicles, and energy efficiency has to be improved by over 50% to achieve the targets of all the three countries.