The difference between those curves isn't "accounting", it's that the emission rate is essentially[1] the time derivative of the CO2 concentration. They have different shapes because they're different (but related) quantities.

It's entirely consistent with precise and good faith emissions measurements for CO2 to be still increasing.

[1] Modulo the seasonal variation, absorption in the ocean, emission from other sources like permafrost thawing, yada yada.