The very low and low GHG emissions scenarios (SSP1-1.9 and 
SSP1-2.6) have CO2 emissions declining to net zero around 2050 and 2070, respectively, followed by varying levels of net negative CO2 
emissions. In addition, Representative Concentration Pathways (RCPs)107 were used by WGI and WGII to assess regional climate changes, 
impacts and risks. {WGI Box SPM.1} (Cross-Section Box.2 Figure 1)
In WGIII, a large number of global modelled emissions pathways were assessed, of which 1202 pathways were categorised based on their 
projected global warming over the 21st century, with categories ranging from pathways that limit warming to 1.5°C with more than 50% 
likelihood108 with no or limited overshoot (C1) to pathways that exceed 4°C (C8). Methods to project global warming associated with the 
modelled pathways were updated to ensure consistency with the AR6 WGI assessment of the climate system response109. {WGIII Box SPM.1,WGIII 
Table 3.1} (Table 3.1, Cross-Section Box.2 Figure 1)
102 In the literature, the terms pathways and scenarios are used interchangeably, with the former more frequently used in relation to climate goals. WGI primarily used the term 
scenarios and WGIII mostly used the term modelled emissions and mitigation pathways. The SYR primarily uses scenarios when referring to WGI and modelled emissions and 
mitigation pathways when referring to WGIII. {WGI Box SPM.1; WGIII footnote 44}
103 Around half of all modelled global emissions pathways assume cost-effective approaches that rely on least-cost mitigation/abatement options globally. The other half look 
at existing policies and regionally and sectorally differentiated actions.  The underlying population assumptions range from 8.5 to 9.7 billion in 2050 and 7.4 to 10.9 billion 
in 2100 (5–95th percentile) starting from 7.6 billion in 2019.