The National Oceanic & Atmospheric Administration (USA) Annual Greenhouse Gas Index (AGGI)
(NOAA Earth System Research Laboratory)
From their Introduction:
"The AGGI is a measure of the climate-warming influence of long-lived trace gases and how that influence has changed since the onset of the industrial revolution. The index was designed to enhance the connection between scientists and society by providing a normalized standard that can be easily understood and followed."

https://www.esrl.noaa.gov/gmd/aggi/aggi.html