Shared socio-economic pathways  have been developed to complement the Representative Concentration Pathways . By design, the RCP emission and concentration pathways were stripped of their association with a certain socio-economic development. Different levels of emissions and climate change along the dimension of the RCPs can hence be explored against the backdrop of different socio-economic development pathways  on the other dimension in a matrix. This integrative SSP-RCP framework is now widely used in the climate impact and policy analysis literature , where climate projections obtained under the RCP scenarios are analysed against a the backdrop of various SSPs. 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, ..., SSPS is used to denote the five socio-economic scenario families. On the other hand, the abbreviations SSP1-1.9, CSP5.8 5 are used to denote the newly developed SSP1.2 6
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report