[skybrian]

It seems to be the difference between carbon emissions and carbon dioxide emissions. From a different web page:

"Global carbon (C) emissions from fossil fuel use were 9.795 gigatonnes (Gt) in 2014 (or 35.9 GtCO2 of carbon dioxide)."

https://www.co2.earth/global-co2-emissions

Carbon's atomic mass is about 12 and oxygen about 16. CO2 is about 27% carbon by weight.

[tunesmith]

Oy. Thanks. I'm really getting a lesson on reading these things more closely.