1. Introduction
As we all know, climate change is the biggest threat to the sustainable development of the world. CO2 is one of the major greenhouse gases causing global climate change. How to reduce the emission of CO2 into the atmosphere is a big concern of the countries around the world. The reaching of Kyoto Protocol is a great progress in the process of mitigating climate change, but it is not enough. Carbon tax, as a GHG-emission-reducing measure, is strongly recommended by scholars and international organizations. Carbon tax is one of the significant economic means of reducing carbon emissions, which is levied by the extend of carbon emissions caused by fossil fuel products such as petrol, aviation fuel and gas in order to reduce the consumption of fuel and emission of carbon dioxide. Some