As the emissions debate hots up the OECD’s International Transport Forum (ITF) for the COP 21 meeting in December to agree an “ambitious package” for shipping.

In a policy brief the ITF called for a package that it said could include three elements. First was an absolute emissions target for shipping related to a pathway of C02 emissions reductions to limit warming to 1.5 – 2 degree centigrade by 2100.

“Considering the size of its current and projected emissions, it would be odd if countries are expected to adhere to emission targets but not the shipping sector, especially since it would be impossible to apportion shipping emissions to countries,” the brief stated.

Second a mandate for the IMO to develop an action plan with concrete measures to reach the emission target.

Third would be a carbon tax for shipping, which would have the advantage of administrative simplicity and would easier to implement than other market based mechanisms.

“The impact on maritime trade would be marginal if the tax were set at around $25 per tonne of CO2. The receipts of such a carbon tax could provide a substantial source of finance for the Green Climate Fund,” it said.

Such a tax would raise $26bn, which could be used for financing climate mitigation projects in developing countries.

In 2012 shipping accounted for 2.2% of global C02 emissions, but given projected trade growth it could reach 14% by 2050 if action is not taken to cut the industry’s emissions.