As several emission updates were due, a new set of emission scenarios was developed in conjunction with the SSPs. Hence, the abbreviation SSP is now used for two things: On the one hand SSP1, SSP2, ... , SSP5 is used to denote the five socio-economic scenario families. On the other hand, the abbreviations SSP1-1.9, SSP1-2.6, ... , SSP5-8.5 are used to denote the newly developed emission scenarios that are the result of an SSP implementation within an integrated assessment model. Those SSP scenarios are bare of climate policy assumption, but in combination with so-called shared policy assumptions , various approximate radiative forcing levels of 1.9, 2.6, ... , or 8.5 W m-2 are reached by the end of the century, respectively.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report