The European Commission has just presented a proposal document involving carbon tax. This would be based both on the energy content and on the emissions of CO2 of fuels. The Commission believes that this move would correct an imbalance which currently exists. The quantity of CO2 emitted would be taxed, but account taken of the amount of energy actually produced by the fuel in question. A minimum monetary level is proposed, in order to avoid wide variations which exist due to different states having different tax levels. The variable part of the tax, based on CO2 output, could lead to diesel, for example, being taxed at around 8% higher than petrol. An Emissions Trading Scheme is also envisaged, as is the possibility of granting a transition period to industries which are traditionally heavy users of diesel. A minimum level of 20 Euros per tonne of CO2 could be in force in 2013.