Maritime transport contributes 2-3% to global greenhouse gas emissions. It is, nevertheless, the only sector which is not yet subject to greenhouse gas (GHG) reduction targets and policies in the European Union (EU). It is imperative that this gap is closed; corresponding policies should be implemented with urgency. One option for addressing GHG emissions from shipping is to incorporate them into the EU Emission Trading System (ETS), as foreseen in the European Green Deal. The inclusion of maritime transport needs to be viewed as part of a policy package since not all barriers to the decarbonization of the sector can be addressed by an ETS with current allowance price levels.