Emissions units

There are a few types of greenhouse gas emissions units which are traded in the frames of the Kyoto Protocol and beyond it. 

The Kyoto Protocol introduced four types of emissions units:

• Certified Emission Reductions (CERs)
• Emission Reduction Units (ERUs)
• Removal Units (RMUs)
• Assigned Amount Units (AAUs)

In the frames of the European Union Emissions Trading Scheme (EU ETS), which is the largest scheme for emissions trading - one of the three Kyoto Protocol mechanisms, it is possible to trade European Union Allowances (EUAs). 

Emissions units that exist beyond the Kyoto Protocol are called Verified Emission Reductions (VERs).