The European Union (EU) Emissions Trading System (ETS) is the cornerstone of the EU’s attempt to decarbonise economic production in Europe. This paper questions the power and class relations that are built into the EU’s choice to address the climate crisis through the legal construction of emissions trading. Drawing on Marxist theory, the paper argues that the cost of emission allowances imposed by the ETS is a form of climate rent. In both the choice of this system and its implementation, the EU prioritises capital accumulation in order to protect the competitiveness of EU firms on the global market. This paper argues that the ETS thus jeopardises the progress of decarbonisation on two grounds. First, the EU’s implementation of the ETS has tended to increase the economic wealth of capital by redistributing economic value away from workers and towards the capitalist class. By raising the cost of essential goods, the ETS will likely damage the reputation of climate action and thus jeopardise public support for decarbonisation. Second, the ETS is part of the EU’s indirect approach to climate policy, which seeks to shape the actions of private capital in the direction of climate objectives. However, the severity of climate change calls instead for the use of law and public power to directly and consciously shape the rapid decarbonisation of society.