0 
and SSP1-2.6
Category 
in WGIII
Category description
GHG emissions scenarios
(SSPx-y*) in WGI & WGII 
RCPy** in
WGI & WGII
C1
limit warming to 1.5°C (>50%)
with no or limited overshoot
Very low (SSP1-1.9)
Low (SSP1-2.6) 
RCP2.6
C2
return warming to 1.5°C (>50%)
after a high overshoot
C3
limit warming to 2°C (>67%)
C4
limit warming to 2°C (>50%)
C5
limit warming to 2.5°C (>50%)
C6
limit warming to 3°C (>50%)
Intermediate (SSP2-4.5)
RCP 4.5
RCP 8.5
C7
limit warming to 4°C (>50%)
High (SSP3-7.0)
C8
exceed warming of 4°C (>50%)
Very high (SSP5-8.5)
Scenarios and warming levels structure our understanding across the 
cause-effect chain from emissions to climate change and risks
CO2 emissions for SSP-based scenarios 
and C1-C8 categories
Vulnerability
Hazard
Response
Risk
Exposure
Climatic
Impact-
Drivers
0
1
2
3
4
5
°C
inﬂuence
shape
* The terminology SSPx-y is used, where ‘SSPx’ refers to the Shared Socio-economic Pathway or ‘SSP’ describing the socio-economic trends 
underlying the scenario, and ‘y’ refers to the approximate level of radiative forcing (in watts per square metre, or Wm–2) resulting from the 
scenario in the year 2100.
** The AR5 scenarios (RCPy), which partly inform the AR6 WGI and WGII assessments, are indexed to a similar set of approximate 2100 radiative 
forcing levels (in W m-2). The SSP scenarios cover a broader range of GHG and air pollutant futures than the RCPs.