I was under the impression GWP (global-warming potential) is the measure of a gas' impact on global warming, in comparison with CO2.
E.g. methane has a GWP of 86 over 20 years - Wikipedia
Comparing paper and ceramic cups for GWP, this article (page 24) shows GWP in kilograms. Does this make sense to show GWP in kg? Can anyone explain why?