How long will the European Union continue to defend its controversial aviation carbon tax scheme amid growing international opposition?

In late February, 29 countries, including China, the United States and Russia, signed a joint declaration in Moscow opposing the E.U. carbon tax scheme, but the European Union has maintained its tough stance. The threat of a trade war will not make the European Union compromise on climate legislation, Connie Hedegaard, the bloc’s commissioner for climate action, recently said in a statement.

International affairs expert Cui Lei believes that the real purpose of the E.U. is to increase its energy security though it introduced the carbon tax plan in the name of reducing emissions. The union relies heavily on oil imported from the Middle East and natural gas from Russia. It hopes to reduce the dependence on foreign energy supplies by imposing a carbon tax on international airlines.

In the eyes of many legal experts and aviation industry insiders, the European Union's unilateral move to force international aviation into its into its Emissions Trading System (ETS) is in violation of international rules.

Tony Tyler, director-general and CEO of the International Air Transport Association (IATA), recently said that the ETS requires airlines to pay for emissions of all flights into and out of European airports, including the portion of those flights outside E.U. airspace. The system violates international aviation rules, and can be easily interpreted as an attack on the sovereignty of other countries. The IATA does not oppose emissions trading, but measures must be globally coordinated and avoid market distortions.

The European Union's carbon tax scheme is "unjustifiable and unlawful," said Ma Jiachang, a professor of aviation law at the School of International Law under China University of Political Science and Law.

In order to prevent the imminent trade war over the carbon tax, the International Civil Aviation Organization (ICAO) under the United Nations recently offered an alternative to the E.U. ETS to break the deadlock between the European Union and potentially affected countries.

The European Union said that it would abandon its carbon tax scheme only if all parties concerned could reach a similar international agreement via the ICAO.

Zhou Qi, a senior research fellow at the Chinese Academy of Social Sciences, said that the scheme is likely to turn into a dead letter if boycotted by too many countries and their airlines.