These occasional corrections are one reason why monthly updates not only add e.g. global mean estimates for the new month, but may slightly change estimates for earlier months. (data.giss.nasa.gov)
Thus, the spatial and seasonal evolution of forcing in the future requires as much scrutiny as the global mean estimate. (ipcc.ch)
On the other hand, the bad performance of your policy means the estimated returns are not earned. (investopedia.com)