Radiative forcing ($\Delta F$)

Radiative forcing is a change in the net downward radiative flux caused by an imposed perturbation, evaluated with a specified adjustment convention before the surface climate responds. State the reference period and whether the diagnostic is at the tropopause or top of the atmosphere. A local seasonal ocean heat flux is not directly interchangeable with global annual radiative forcing.

For $F(C)-F(C_0)=a\ln (C/C_0)$, a further annual concentration increment produces $a\ln [(C+\Delta C)/C]$, whereas the accumulated forcing from the original baseline is $a\ln (C/C_0)$. The former can decrease as $C$ rises while the latter increases. Maintaining a short-lived compensating aerosol burden also requires replacement, not only compensation of the next increment.