CO2e

From Emissions Wiki

CO₂e (or CO₂eq) is the universal unit of measurement used to indicate the global warming potential (GWP) of each of the greenhouse gases. It is used to evaluate the impacts of releasing different greenhouse gases.

Confusingly, 1 'Tonne of CO2e' may not in fact have a mass of 1 tonne, it depends greatly on the GHG being measured.