Fossil fuels are responsible for about 60% of greenhouse gases emissions (in CO2 equivalent), the remaining 40% being split between: deforestation, farming and various chemical processes (to make concrete, to reduce iron ore, to make fertilizer from natural gas, etc.). Your equation seems to solely focus on these 60%, so it's quite incomplete, given that we also need to get rid of the remaining 40%.

For example methane and nitrous oxide, two extremely potent greenhouse gases, are mostly by-product of agriculture/cattle rearing: methane from cows and rice fields, nitrous oxide from the usage of fertilizers (from memory, I might be wrong).

Another example: the chemical process behind concrete production (CaCO3 -> CaO + CO2) emits more CO2 (about 4% of global emissions) than the world airplane fleet (about 2% of global emissions). That's without accounting for the energy necessary to trigger the chemical process, usually coming from fossil fuel...